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Conversion of units
Conversion of units
is the conversion between different units of measurement for the same quantity, typically through multiplicative conversion factors.

Contents

1 Techniques

1.1 Process overview 1.2 Conversion factors 1.3 Software tools

2 Tables of conversion factors

2.1 Length 2.2 Area 2.3 Volume 2.4 Plane angle 2.5 Solid angle 2.6 Mass 2.7 Density 2.8 Time 2.9 Frequency 2.10 Speed
Speed
or velocity 2.11 Flow (volume) 2.12 Acceleration 2.13 Force 2.14 Pressure
Pressure
or mechanical stress 2.15 Torque
Torque
or moment of force 2.16 Energy 2.17 Power or heat flow rate 2.18 Action 2.19 Dynamic viscosity 2.20 Kinematic viscosity 2.21 Electric current 2.22 Electric charge 2.23 Electric dipole 2.24 Electromotive force, electric potential difference 2.25 Electrical resistance 2.26 Capacitance 2.27 Magnetic flux 2.28 Magnetic flux
Magnetic flux
density 2.29 Inductance 2.30 Temperature 2.31 Information entropy 2.32 Luminous intensity 2.33 Luminance 2.34 Luminous flux 2.35 Illuminance 2.36 Radiation – source activity 2.37 Radiation – exposure 2.38 Radiation – absorbed dose 2.39 Radiation – equivalent dose

3 See also 4 Notes and references 5 External links

Techniques[edit] See also: Dimensional analysis Process overview[edit] The process of conversion depends on the specific situation and the intended purpose. This may be governed by regulation, contract, technical specifications or other published standards. Engineering judgment may include such factors as:

The precision and accuracy of measurement and the associated uncertainty of measurement. The statistical confidence interval or tolerance interval of the initial measurement. The number of significant figures of the measurement. The intended use of the measurement including the engineering tolerances. Historical definitions of the units and their derivatives used in old measurements; e.g., international foot vs. US survey foot.

Some conversions from one system of units to another need to be exact, without increasing or decreasing the precision of the first measurement. This is sometimes called soft conversion. It does not involve changing the physical configuration of the item being measured. By contrast, a hard conversion or an adaptive conversion may not be exactly equivalent. It changes the measurement to convenient and workable numbers and units in the new system. It sometimes involves a slightly different configuration, or size substitution, of the item.[clarification needed] Nominal values are sometimes allowed and used. Conversion factors[edit] A conversion factor is used to change the units of a measured quantity without changing its value. The unity bracket method of unit conversion[1] consists of a fraction in which the denominator is equal to the numerator, but they are in different units. Because of the identity property of multiplication, the value of a number will not change as long as it is multiplied by one.[2] Also, if the numerator and denominator of a fraction are equal to each other, then the fraction is equal to one. So as long as the numerator and denominator of the fraction are equivalent, they will not affect the value of the measured quantity. Software tools[edit] There are many conversion tools. They are found in the function libraries of applications such as spreadsheets databases, in calculators, and in macro packages and plugins for many other applications such as the mathematical, scientific and technical applications. There are many standalone applications that offer the thousands of the various units with conversions. For example, the free software movement offers a command line utility GNU units for Linux and Windows. Tables of conversion factors[edit]

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This article gives lists of conversion factors for each of a number of physical quantities, which are listed in the index. For each physical quantity, a number of different units (some only of historical interest) are shown and expressed in terms of the corresponding SI unit. Conversions between units in the metric system are defined by their prefixes (for example, 1 kilogram = 1000 grams, 1 milligram = 0.001 grams) and are thus not listed in this article. Exceptions are made if the unit is commonly known by another name (for example, 1 micron = 10−6 metre). Within each table, the units are listed alphabetically, and the SI units (base or derived) are highlighted.

Legend

Symbol Definition

≡ exactly equal

≈ approximately equal to

digits indicates that digits repeat infinitely (e.g. 8.294369 corresponds to 8.294369369369369…)

(H) of chiefly historical interest

Length[edit]

Length

Name of unit Symbol Definition Relation to SI units

ångström Å ≡ 6990100000000000000♠1×10−10 m ≡ 0.1 nm

astronomical unit AU ≡ 7011149597870700000♠149597870700 m ≈ Distance from Earth to Sun ≡ 7011149597870700000♠149597870700 m [3]

barleycorn (H)   = ​1⁄3 in (see note above about rounding) ≈ 8.46×10−3 m

bohr, atomic unit of length a0 = Bohr radius of hydrogen ≈ 6989529177210920000♠5.2917721092(17)×10−11 m[4]

cable length (imperial)   ≡ 608 ft ≈ 185.3184 m

cable length (International)   ≡ ​1⁄10 nmi ≡ 185.2 m

cable length (US)   ≡ 720 ft = 219.456 m

chain (Gunter's; Surveyor's) ch ≡ 66 ft (US) ≡ 4 rods [5] ≈ 7001201168400000000♠20.11684 m

cubit (H)   ≡ Distance from fingers to elbow ≈ 18 in ≈ 0.5 m

ell (H) ell ≡ 45 in [6] (In England usually) = 1.143 m

fathom ftm ≡ 6 ft [6] = 1.8288 m

fermi fm ≡ 6985100000000000000♠1×10−15 m[6] ≡ 6985100000000000000♠1×10−15 m

finger   ≡ ​7⁄8 in = 6998222250000000000♠0.022225 m

finger (cloth)   ≡ ​4 1⁄2 in = 0.1143 m

foot (Benoît) (H) ft (Ben)

≈ 6999304799735000000♠0.304799735 m

foot (Cape) (H)   Legally defined as 1.033 English feet in 1859 ≈ 6999314858000000000♠0.314858 m

foot (Clarke's) (H) ft (Cla)

≈ 6999304797265400000♠0.3047972654 m

foot (Indian) (H) ft Ind

≈ 6999304799514000000♠0.304799514 m

foot, metric mf ≡ √​1⁄10 m[citation needed] ≈ 0.31622776602 m

foot, metric (long) lmf ≡ ​1⁄3 m ≈ 0.3 m

foot, metric (short) smf ≡ 0.30 m ≡ 0.30 m

foot (International) ft ≡ 0.3048 m ≡ ​1⁄3 yd ≡ 12 inches ≡ 0.3048 m

foot (Sear's) (H) ft (Sear)

≈ 6999304799470000000♠0.30479947 m

foot (US Survey) ft (US) ≡ ​7003120000000000000♠1200⁄7003393700000000000♠3937 m [7] ≈ 6999304800610000000♠0.304800610 m

french; charriere F ≡ ​1⁄3 mm = 0.3 ×10−3 m

furlong fur ≡ 10 chains = 660 ft = 220 yd [6] = 201.168 m

hand   ≡ 4 in [6] ≡ 0.1016 m

inch (International) in ≡ 2.54 cm ≡ ​1⁄36 yd ≡ ​1⁄12 ft ≡ 0.0254 m

league (land) lea ≈ 1 hour walk, Currently defined in US as 3 Statute miles,[5] but historically varied from 2 to 9 km ≈ 7003482800000000000♠4828 m

light-day   ≡ 24 light-hours ≡ 7013259020683712000♠2.59020683712×1013 m

light-hour   ≡ 60 light-minutes ≡ 7012107925284880000♠1.0792528488×1012 m

light-minute   ≡ 60 light-seconds ≡ 7010179875474800000♠1.798754748×1010 m

light-second   ≡ Distance light travels in one second in vacuum ≡ 7008299792458000000♠299792458 m

light-year ly ≡ Distance light travels in vacuum in 365.25 days [8] = 7015946073047258080♠9.4607304725808×1015 m

line ln ≡ ​1⁄12 in [9] = 0.002116 m

link (Gunter's; Surveyor's) lnk ≡ ​1⁄100 ch [6] ≡ 0.66 ft (US) ≡ 7.92 in ≈ 6999201168400000000♠0.2011684 m

link (Ramsden's; Engineer's) lnk ≡ 1 ft [6] = 0.3048 m

metre (SI base unit) (meter) m ≡ Distance light travels in ​1⁄7008299792458000000♠299792458 of a second in vacuum.[10] ≈ ​1⁄7007100000000000000♠10000000 of the distance from equator to pole. ≡ 1 m

mickey   ≡ ​1⁄200 in = 6996127000000000000♠1.27×10−4 m

micrometre (old: micron) μ; μm

≡ 6994100000000000000♠1×10−6 m

mil; thou mil ≡ 6995254000000000000♠1×10−3 in ≡ 6995254000000000000♠2.54×10−5 m

mil (Sweden and Norway) mil ≡ 10 km = 7004100000000000000♠10000 m

mile (geographical) (H)

≡ 7003185379360000000♠6082 ft = 7003185379360000000♠1853.7936 m

mile (international) mi ≡ 80 chains ≡ 7003160934400000000♠5280 ft ≡ 7003160934400000000♠1760 yd ≡ 7003160934400000000♠1609.344 m

mile (tactical or data)

≡ 7003182880000000000♠6000 ft ≡ 7003182880000000000♠1828.8 m

mile (telegraph) (H) mi ≡ 7003185531760000000♠6087 ft = 7003185531760000000♠1855.3176 m

mile (US Survey) mi ≡ 7003528000000000000♠5280 US Survey feet ≡ (7003528000000000000♠5280 × ​7003120000000000000♠1200⁄7003393700000000000♠3937) m ≈ 7003160934721900000♠1609.347219 m

nail (cloth)   ≡ ​2 1⁄4 in [6] = 6998571500000000000♠0.05715 m

nanometre nm ≡ 6991100000000000000♠1×10−9 m ≡ 6991100000000000000♠1×10−9 m

nautical league NL; nl ≡ 3 nmi [6] = 7003555600000000000♠5556 m

nautical mile (Admiralty) NM (Adm); nmi (Adm) = 7003185318400000000♠6080 ft = 7003185318400000000♠1853.184 m

nautical mile (international) NM; nmi ≡ 7003185200000000000♠1852 m[11] ≡ 7003185200000000000♠1852 m

nautical mile (US pre 1954)

≡ 1853.248 m ≡ 1853.248 m

pace   ≡ 2.5 ft [6] = 0.762 m

palm   ≡ 3 in [6] = 0.0762 m

parsec pc Distant point with a parallax shift of one arc second from a base of one astronomical unit. ≡ 7005648000000000000♠648000/π AU[12][13] ≈ 7016308567758149137♠30856775814913700 m[14]

pica   ≡ 12 points Dependent on point measures.

point (American, English)[15][16] pt ≡ ​1⁄72.272 in ≈ 6996351450000000000♠0.000351450 m

point (Didot; European) [16][17] pt ≡ ​1⁄12 × ​1⁄72 of pied du roi;

After 1878: ≡ ​5⁄133 cm ≈ 6996375970000000000♠0.00037597 m;

After 1878: ≈ 6996375939850000000♠0.00037593985 m

point (PostScript) [15] pt ≡ ​1⁄72 in = 0.0003527 m

point (TeX) [15] pt ≡ ​1⁄72.27 in = 0.0003514598 m

quarter   ≡ ​1⁄4 yd = 0.2286 m

rod; pole; perch (H) rd ≡ ​16 1⁄2 ft = 5.0292 m

rope (H) rope ≡ 20 ft [6] = 6.096 m

shaku (Japan)

≡ 10/33 m ≈ 0.303 0303 m

span (H)    ≡ 9 in [6] = 0.2286 m

spat [18]

≡ 7012100000000000000♠1×1012 m

stick (H)   ≡ 2 in = 0.0508 m

picometre (old: bicron, stigma) pm

≡ 6988100000000000000♠1×10−12 m

twip twp ≡ ​1⁄1440 in = 1.7638×10−5 m

x unit; siegbahn xu

≈ 6987100210000000000♠1.0021×10−13 m [6]

yard (International) yd ≡ 0.9144 m [7] ≡ 3 ft ≡ 36 in ≡ 0.9144 m

Area[edit]

Area

Name of unit Symbol Definition Relation to SI units

acre (international) ac ≡ 1 ch × 10 ch = 7003404685642240000♠4840 sq yd ≡ 7003404685642240000♠4046.8564224 m2

acre (US survey) ac ≡ 10 sq ch = 7003404685642240000♠4840 sq yd, also 7003404685642240000♠43560 sq ft ≈ 7003404687300000000♠4046.873 m2[19]

are a ≡ 100 m2 ≡ 100 m2

barn b ≡ 10−28 m2 ≡ 10−28 m2

barony   ≡ 7003400000000000000♠4000 ac ≡ 7007161874256895999♠1.61874256896×107 m2

board bd ≡ 1 in × 1 ft ≡ 6997774192000000000♠7.74192×10−3 m2

boiler horsepower equivalent direct radiation bhp EDR ≡ 1 ft2 × 1 bhp / (240 BTUIT/h) ≈ 7001129581740000000♠12.958174 m2

circular inch circ in ≡ ​π⁄4 sq in ≈ 6996506707500000000♠5.067075×10−4 m2

circular mil; circular thou circ mil ≡ ​π⁄4 mil2 ≈ 6990506707500000000♠5.067075×10−10 m2

cord   ≡ 192 bd ≡ 7000148644864000000♠1.48644864 m2

cuerda (PR Survey) cda ≡ 1 cda x 1 cda = 6999971222000000000♠0.971222 acre ≡ 7003393039562500000♠3930.395625 m2

dunam   ≡ 7003100000000000000♠1000 m2 = 7003100000000000000♠1000 m2

guntha (India)   ≡ 121 sq yd ≈ 101.17 m2

hectare ha ≡ 7004100000000000000♠10000 m2 ≡ 7004100000000000000♠10000 m2

hide   ≈ 120 ac (variable) ≈ 7005500000000000000♠5×105 m2

rood ro ≡ ​1⁄4 ac = 7003101171410560000♠1011.7141056 m2

ping

≡ ​20⁄11 m × ​20⁄11 m ≈ 7000330600000000000♠3.306 m2

section

≡ 1 mi × 1 mi = 7006258998811033599♠2.589988110336×106 m2

shed   ≡ 10−52 m2 = 10−52 m2

square (roofing)

≡ 10 ft × 10 ft = 7000929030400000000♠9.290304 m2

square chain (international) sq ch ≡ 66 ft × 66 ft = ​1⁄10 ac ≡ 7002404685642240000♠404.68564224 m2

square chain (US Survey) sq ch ≡ 66 ft (US) × 66 ft (US) = ​1⁄10 US survey acre ≈ 7002404687300000000♠404.6873 m2

square foot sq ft ≡ 1 ft × 1 ft ≡ 6998929030400000000♠9.290304×10−2 m2

square foot (US Survey) sq ft ≡ 1 ft (US) × 1 ft (US) ≈ 6998929034116132750♠9.2903411613275×10−2 m2

square inch sq in ≡ 1 in × 1 in ≡ 6996645160000000000♠6.4516×10−4 m2

square kilometre km2 ≡ 1 km × 1 km = 106 m2

square link (Gunter's)(International) sq lnk ≡ 1 lnk × 1 lnk ≡ 0.66 ft × 0.66 ft = 6998404685642240000♠4.0468564224×10−2 m2

square link (Gunter's)(US Survey) sq lnk ≡ 1 lnk × 1 lnk ≡ 0.66 ft (US) × 0.66 ft (US) ≈ 6998404687200000000♠4.046872×10−2 m2

square link (Ramsden's) sq lnk ≡ 1 lnk × 1 lnk ≡ 1 ft × 1 ft = 6998929030400000000♠0.09290304 m2

square metre (SI unit) m2 ≡ 1 m × 1 m = 1 m2

square mil; square thou sq mil ≡ 1 mil × 1 mil = 6990645160000000000♠6.4516×10−10 m2

square mile sq mi ≡ 1 mi × 1 mi ≡ 7006258998811033599♠2.589988110336×106 m2

square mile (US Survey) sq mi ≡ 1 mi (US) × 1 mi (US) ≈ 7006258999846999999♠2.58999847×106 m2

square rod/pole/perch sq rd ≡ 1 rd × 1 rd = 7001252928526400000♠25.29285264 m2

square yard (International) sq yd ≡ 1 yd × 1 yd ≡ 6999836127360000000♠0.83612736 m2

stremma   ≡ 7003100000000000000♠1000 m2 = 7003100000000000000♠1000 m2

township   ≡ 36 sq mi (US) ≈ 7007932399400000000♠9.323994×107 m2

yardland   ≈ 30 ac ≈ 7005120000000000000♠1.2×105 m2

Volume[edit]

Volume

Name of unit Symbol Definition Relation to SI units

acre-foot ac ft ≡ 1 ac x 1 ft = 7003123348183754752♠43560 cu ft = 7003123348183754752♠1233.48183754752 m3

acre-inch   ≡ 1 ac × 1 in = 7002102790153128960♠102.79015312896 m3

barrel (imperial) bl (imp) ≡ 36 gal (imp) = 6999163659240000000♠0.16365924 m3

barrel (petroleum); archaic blue-barrel bl; bbl ≡ 42 gal (US) = 6999158987294928000♠0.158987294928 m3

barrel (US dry) bl (US) ≡ 105 qt (US) = 105/32 bu (US lvl) = 6999115628198985075♠0.115628198985075 m3

barrel (US fluid) fl bl (US) ≡ ​31 1⁄2 gal (US) = 6999119240471196000♠0.119240471196 m3

board-foot fbm ≡ 144 cu in ≡ 6997235973721600000♠2.359737216×10−3 m3

bucket (imperial) bkt ≡ 4 gal (imp) = 6998181843600000000♠0.01818436 m3

bushel (imperial) bu (imp) ≡ 8 gal (imp) = 6998363687200000000♠0.03636872 m3

bushel (US dry heaped) bu (US) ≡ ​1 1⁄4 bu (US lvl) = 6998440488377086000♠0.0440488377086 m3

bushel (US dry level) bu (US lvl) ≡ 6998352390701668800♠2150.42 cu in = 6998352390701668800♠0.03523907016688 m3

butt, pipe   ≡ 126 gal (wine) = 6999476961884784000♠0.476961884784 m3

coomb   ≡ 4 bu (imp) = 6999145474880000000♠0.14547488 m3

cord (firewood)   ≡ 8 ft × 4 ft × 4 ft = 7000362455636377600♠3.624556363776 m3

cord-foot   ≡ 16 cu ft = 6999453069545472000♠0.453069545472 m3

cubic fathom cu fm ≡ 1 fm × 1 fm × 1 fm = 7000611643886387200♠6.116438863872 m3

cubic foot ft3 ≡ 1 ft × 1 ft × 1 ft ≡ 6998283168465920000♠0.028316846592 m3

cubic inch in3 ≡ 1 in × 1 in × 1 in ≡ 6995163870640000000♠16.387064×10−6 m3

cubic metre (SI unit) m3 ≡ 1 m × 1 m × 1 m ≡ 1 m3

cubic mile cu mi ≡ 1 mi × 1 mi × 1 mi ≡ 7009416818182544057♠4168181825.440579584 m3

cubic yard yd3 ≡ 27 cu ft ≡ 6999764554857984000♠0.764554857984 m3

cup (breakfast)   ≡ 10 fl oz (imp) = 6996284130625000000♠284.130625×10−6 m3

cup (Canadian) c (CA) ≡ 8 fl oz (imp) = 6996227304500000000♠227.3045×10−6 m3

cup (metric) c ≡ 6996250000000000000♠250.0×10−6 m3 = 6996250000000000000♠250.0×10−6 m3

cup (US customary) c (US) ≡ 8 US fl oz ≡ ​1⁄16 gal (US) = 6996236588236499999♠236.5882365×10−6 m3

cup (US food nutrition labeling) c (US) ≡ 240 mL[20] = 6996240000000000000♠2.4×10−4 m3

dash (imperial)   ≡ ​1⁄384 gi (imp) = ​1⁄2 pinch (imp) = 369.961751302083×10−9 m3

dash (US)   ≡ ​1⁄96 US fl oz = ​1⁄2 US pinch = 6993308057599609375♠308.057599609375×10−9 m3

dessertspoon (imperial)   ≡ ​1⁄12 gi (imp) = 11.8387760416×10−6 m3

drop (imperial) gtt ≡ ​1⁄288 fl oz (imp) = 98.6564670138×10−9 m3

drop (imperial) (alt) gtt ≡ ​1⁄7003182400000000000♠1824 gi (imp) ≈ 6992778866840000000♠77.886684×10−9 m3

drop (medical)   ≡ ​0.9964⁄12 ml = 83.03×10−9 m3

drop (medical)   ≡ ​1⁄12 ml = 83.3×10−9 m3

drop (metric)   ≡ ​1⁄20 mL = 6992500000000000000♠50.0×10−9 m3

drop (US) gtt ≡ ​1⁄360 US fl oz = 82.14869322916×10−9 m3

drop (US) (alt) gtt ≡ ​1⁄456 US fl oz ≈ 6992648542314967100♠64.85423149671×10−9 m3

drop (US) (alt) gtt ≡ ​1⁄576 US fl oz ≈ 6992513429332682300♠51.34293326823×10−9 m3

fifth   ≡ ​1⁄5 US gal = 6996757082356799999♠757.0823568×10−6 m3

firkin   ≡ 9 gal (imp) = 6998409148100000000♠0.04091481 m3

fluid drachm (imperial) fl dr ≡ ​1⁄8 fl oz (imp) = 6994355163281250000♠3.5516328125×10−6 m3

fluid dram (US); US fluidram fl dr ≡ ​1⁄8 US fl oz = 6994369669119531250♠3.6966911953125×10−6 m3

fluid scruple (imperial) fl s ≡ ​1⁄24 fl oz (imp) = 1.18387760416×10−6 m3

gallon (beer) beer gal ≡ 282 cu in = 6997462115204800000♠4.621152048×10−3 m3

gallon (imperial) gal (imp) ≡ 6997454609000000000♠4.54609 L ≡ 6997454609000000000♠4.54609×10−3 m3

gallon (US dry) gal (US) ≡ ​1⁄8 bu (US lvl) = 6997440488377086000♠4.40488377086×10−3 m3

gallon (US fluid; Wine) gal (US) ≡ 231 cu in ≡ 6997378541178400000♠3.785411784×10−3 m3

gill (imperial); Noggin gi (imp); nog ≡ 5 fl oz (imp) = 6996142065312500000♠142.0653125×10−6 m3

gill (US) gi (US) ≡ 4 US fl oz = 6996118294118249999♠118.29411825×10−6 m3

hogshead (imperial) hhd (imp) ≡ 2 bl (imp) = 6999327318480000000♠0.32731848 m3

hogshead (US) hhd (US) ≡ 2 fl bl (US) = 6999238480942392000♠0.238480942392 m3

jigger (bartending)   ≡ ​1 1⁄2 US fl oz ≈ 6995443599999999999♠44.36×10−6 m3

kilderkin   ≡ 18 gal (imp) = 6998818296200000000♠0.08182962 m3

lambda λ ≡ 1 mm3 = 6991100000000000000♠1×10−9 m3

last   ≡ 80 bu (imp) = 7000290949760000000♠2.9094976 m3

litre (liter) L ≡ 1 dm3 [21] ≡ 0.001 m3

load   ≡ 50 cu ft = 7000141584232960000♠1.4158423296 m3

minim (imperial) min ≡ ​1⁄480 fl oz (imp) = 1/60 fl dr (imp) = 59.1938802083×10−9 m3

minim (US) min ≡ ​1⁄480 US fl oz = ​1⁄60 US fl dr = 6992616115199218750♠61.611519921875×10−9 m3

ounce (fluid imperial) fl oz (imp) ≡ ​1⁄160 gal (imp) ≡ 6995284130625000000♠28.4130625×10−6 m3

ounce (fluid US customary) US fl oz ≡ ​1⁄128 gal (US) ≡ 6995295735295625000♠29.5735295625×10−6 m3

ounce (fluid US food nutrition labeling) US fl oz ≡ 30 mL[20] ≡ 6995300000000000000♠3×10−5 m3

peck (imperial) pk ≡ 2 gal (imp) = 6997909218000000000♠9.09218×10−3 m3

peck (US dry) pk ≡ ​1⁄4 US lvl bu = 6997880976754172000♠8.80976754172×10−3 m3

perch per ≡ ​16 1⁄2 ft × ​1 1⁄2 ft × 1 ft = 6999700841953152000♠0.700841953152 m3

pinch (imperial)   ≡ ​1⁄192 gi (imp) = 1/16 tsp (imp) = 739.92350260416×10−9 m3

pinch (US)   ≡ ​1⁄48 US fl oz = 1/16 US tsp = 6993616115199218750♠616.11519921875×10−9 m3

pint (imperial) pt (imp) ≡ ​1⁄8 gal (imp) = 6996568261250000000♠568.26125×10−6 m3

pint (US dry) pt (US dry) ≡ ​1⁄64 bu (US lvl) ≡ ​1⁄8 gal (US dry) = 6996550610471357500♠550.6104713575×10−6 m3

pint (US fluid) pt (US fl) ≡ ​1⁄8 gal (US) = 6996473176472999999♠473.176473×10−6 m3

pony   ≡ ​3⁄4 US fl oz = 6995221801471718750♠22.180147171875×10−6 m3

pottle; quartern   ≡ ​1⁄2 gal (imp) = 80 fl oz (imp) = 6997227304500000000♠2.273045×10−3 m3

quart (imperial) qt (imp) ≡ ​1⁄4 gal (imp) = 6997113652250000000♠1.1365225×10−3 m3

quart (US dry) qt (US) ≡ ​1⁄32 bu (US lvl) = ​1⁄4 gal (US dry) = 6997110122094271500♠1.101220942715×10−3 m3

quart (US fluid) qt (US) ≡ ​1⁄4 gal (US fl) = 6996946352945999999♠946.352946×10−6 m3

quarter; pail   ≡ 8 bu (imp) = 6999290949760000000♠0.29094976 m3

register ton   ≡ 100 cu ft = 7000283168465920000♠2.8316846592 m3

sack (imperial); bag   ≡ 3 bu (imp)[citation needed] = 6999109106160000000♠0.10910616 m3

sack (US)   ≡ 3 bu (US lvl) = 6999105717210500640♠0.10571721050064 m3

seam   ≡ 8 bu (US lvl)[citation needed] = 6999281912561335040♠0.28191256133504 m3

shot (US)   usually 1.5 US fl oz[18] ≈ 6995440000000000000♠44×10−6 m3

strike (imperial)   ≡ 2 bu (imp) = 6998727374400000000♠0.07273744 m3

strike (US)   ≡ 2 bu (US lvl) = 6998704781403337600♠0.07047814033376 m3

tablespoon (Australian metric)  

≡ 6995199999999999999♠20.0×10−6 m3

tablespoon (Canadian) tbsp ≡ ​1⁄2 fl oz (imp) = 6995142065312500000♠14.20653125×10−6 m3

tablespoon (imperial) tbsp ≡ ​5⁄8 fl oz (imp) = 6995177581640625000♠17.7581640625×10−6 m3

tablespoon (metric)  

≡ 6995150000000000000♠15.0×10−6 m3

tablespoon (US customary) tbsp ≡ ​1⁄2 US fl oz = 6995147867647812500♠14.78676478125×10−6 m3

tablespoon (US food nutrition labeling) tbsp ≡ 15 mL[20] = 6995150000000000000♠1.5×10−5 m3

teaspoon (Canadian) tsp ≡ ​1⁄6 fl oz (imp) = 4.735510416×10−6 m3

teaspoon (imperial) tsp ≡ ​1⁄24 gi (imp) = 5.91938802083×10−6 m3

teaspoon (metric)   ≡ 6994499999999999999♠5.0×10−6 m3 = 6994499999999999999♠5.0×10−6 m3

teaspoon (US customary) tsp ≡ ​1⁄6 US fl oz = 6994492892159374999♠4.92892159375×10−6 m3

teaspoon (US food nutrition labeling) tsp ≡ 5 mL[20] = 6994499999999999999♠5×10−6 m3

timber foot   ≡ 1 cu ft = 6998283168465920000♠0.028316846592 m3

ton (displacement)   ≡ 35 cu ft = 6999991089630720000♠0.99108963072 m3

ton (freight)   ≡ 40 cu ft = 7000113267386368000♠1.13267386368 m3

ton (water)   ≡ 28 bu (imp) = 7000101832416000000♠1.01832416 m3

tun   ≡ 252 gal (wine) = 6999953923769568000♠0.953923769568 m3

wey (US)   ≡ 40 bu (US lvl) = 7000140956280667520♠1.4095628066752 m3

Plane angle[edit]

Plane angle

Name of unit Symbol Definition Relation to SI units

angular mil µ ≡ ​2π⁄7003640000000000000♠6400 rad ≈ 6994981747999999999♠0.981748×10−3 rad

arcminute; MOA ' ≡ ​1°⁄60 ≈ 6994290888000000000♠0.290888×10−3 rad

arcsecond " ≡ ​1°⁄7003360000000000000♠3600 ≈ 6992484813700000000♠4.848137×10−6 rad

centesimal minute of arc ' ≡ ​1⁄100 grad ≈ 6994157080000000000♠0.157080×10−3 rad

centesimal second of arc " ≡ ​1⁄7004100000000000000♠10000 grad ≈ 6992157079600000000♠1.570796×10−6 rad

degree (of arc) ° ≡ ​1⁄360 of a revolution ≡ ​π⁄180 rad ≈ 6996174532929999999♠17.453293×10−3 rad

grad; gradian; gon grad ≡ ​1⁄400 of a revolution ≡ ​π⁄200 rad ≡ 0.9° ≈ 6996157079630000000♠15.707963×10−3 rad

octant   ≡ 45° ≈ 6997785398000000000♠0.785398 rad

quadrant   ≡ 90° ≈ 6998157079600000000♠1.570796 rad

radian (SI unit) rad The angle subtended at the center of a circle by an arc whose length is equal to the circle's radius. One full revolution encompasses 2π radians.

= 1 rad

sextant   ≡ 60° ≈ 6998104719800000000♠1.047198 rad

sign   ≡ 30° ≈ 6997523599000000000♠0.523599 rad

Solid angle[edit]

Solid angle

Name of unit Symbol Definition Relation to SI units

spat

≡ 4π sr[18] – The solid angle subtended by a sphere at its centre. ≈ 7001125663699999999♠12.56637 sr

square degree deg2; sq.deg.; (°)2 ≡ (​π⁄180)2 sr ≈ 6996304620000000000♠0.30462×10−3 sr

steradian (SI unit) sr The solid angle subtended at the center of a sphere of radius r by a portion of the surface of the sphere having an area r2. A sphere subtends 4π sr.[18]

= 1 sr

Mass[edit] Notes:

See Weight
Weight
for detail of mass/weight distinction and conversion. Avoirdupois
Avoirdupois
is a system of mass based on a pound of 16 ounces, while Troy weight
Troy weight
is the system of mass where 12 troy ounces equals one troy pound. In this table, the unit gee is used to denote standard gravity in order to avoid confusion with the "g" symbol for grams.

Mass

Name of unit Symbol Definition Relation to SI units

atomic mass unit, unified u; AMU Same as dalton (see below) ≈ 6973166053904000000♠1.660539040(20)×10−27 kg[22]

atomic unit of mass, electron rest mass me

≈ 6969910938291000000♠9.10938291(40)×10−31 kg[23]

bag (coffee)   ≡ 60 kg = 60 kg

bag (Portland cement)   ≡ 94 lb av = 7001426376827800000♠42.63768278 kg

barge   ≡ ​22 1⁄2 short ton = 7004204116566500000♠20411.65665 kg

carat kt ≡ ​3 1⁄6 gr = 7002205196548000000♠205.1965483 mg

carat (metric) ct ≡ 200 mg = 200 mg

clove   ≡ 8 lb av = 7000362873896000000♠3.62873896 kg

crith   ≡ mass of 1 L of hydrogen gas at STP ≈ 89.9349 mg

dalton Da 1/12 the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest ≈ 6973166053892099999♠1.660538921(73)×10−27 kg[22]

dram (apothecary; troy) dr t ≡ 60 gr = 6997388793460000000♠3.8879346 g

dram (avoirdupois) dr av ≡ ​27 11⁄32 gr = 6997177184519531250♠1.7718451953125 g

electronvolt eV ≡ 1 eV (energy unit) / c2 = 6964178266184000000♠1.78266184(45)×10−36 kg[24]

gamma γ ≡ 1 μg = 1 μg

grain gr ≡ ​1⁄7003700000000000000♠7000 lb av ≡ 6995647989100000000♠64.79891 mg

grave gv. grave was the original name of the kilogram ≡ 1 kg

hundredweight (long) long cwt or cwt ≡ 112 lb av = 7001508023454400000♠50.80234544 kg

hundredweight (short); cental sh cwt ≡ 100 lb av = 7001453592370000000♠45.359237 kg

kilogram (kilogramme) kg ≡ mass of the prototype near Paris ≈ mass of 1 litre of water ≡ 1 kg (SI base unit)[10]

kip kip ≡ 7002453592370000000♠1000 lb av = 7002453592370000000♠453.59237 kg

mark   ≡ 8 oz t = 6999248827814400000♠248.8278144 g

mite   ≡ ​1⁄20 gr = 6994323994550000000♠3.2399455 mg

mite (metric)   ≡ ​1⁄20 g = 50 mg

ounce (apothecary; troy) oz t ≡ ​1⁄12 lb t = 6998311034768000000♠31.1034768 g

ounce (avoirdupois) oz av ≡ ​1⁄16 lb = 6998283495231250000♠28.349523125 g

ounce (US food nutrition labelling) oz ≡ 28 g[20] = 28 g

pennyweight dwt; pwt ≡ ​1⁄20 oz t = 6997155517384000000♠1.55517384 g

point   ≡ ​1⁄100 ct = 2 mg

pound (avoirdupois) lb av ≡ 6999453592370000000♠0.45359237 kg = 7003700000000000000♠7000 grains ≡ 6999453592370000000♠0.45359237 kg

pound (metric)   ≡ 500 g = 500 g

pound (troy) lb t ≡ 7003576000000000000♠5760 grains = 6999373241721600000♠0.3732417216 kg

quarter (imperial)   ≡ ​1⁄4 long cwt = 2 st = 28 lb av = 7001127005863600000♠12.70058636 kg

quarter (informal)   ≡ ​1⁄4 short ton = 7002226796185000000♠226.796185 kg

quarter, long (informal)   ≡ ​1⁄4 long ton = 7002254011727200000♠254.0117272 kg

quintal (metric) q ≡ 100 kg = 100 kg

scruple (apothecary) s ap ≡ 20 gr = 6997129597820000000♠1.2959782 g

sheet   ≡ ​1⁄700 lb av = 647.9891 mg

slug; geepound; hyl slug ≡ 1 ɡ0 × 1 lb av × 1 s2/ft ≈ 7001145939030000000♠14.593903 kg

stone st ≡ 14 lb av = 7000635029318000000♠6.35029318 kg

ton, assay (long) AT ≡ 1 mg × 1 long ton ÷ 1 oz t = 32.6 g

ton, assay (short) AT ≡ 1 mg × 1 short ton ÷ 1 oz t = 29.16 g

ton, long long tn or ton ≡ 7003101604690880000♠2240 lb = 7003101604690880000♠1016.0469088 kg

ton, short sh tn ≡ 7002907184740000000♠2000 lb = 7002907184740000000♠907.18474 kg

tonne (mts unit) t ≡ 7003100000000000000♠1000 kg = 7003100000000000000♠1000 kg

wey   ≡ 252 lb = 18 st = 7002114305277240000♠114.30527724 kg (variants exist)

Zentner Ztr. Definitions vary.[18][25]

Density[edit]

Density

Name of unit Symbol Definition Relation to SI units

gram per millilitre g/mL ≡ g/mL = 7003100000000000000♠1000 kg/m3

kilogram per cubic metre (SI unit) kg/m3 ≡ kg/m3 = 1 kg/m3

kilogram per litre kg/L ≡ kg/L = 7003100000000000000♠1000 kg/m3

ounce (avoirdupois) per cubic foot oz/ft3 ≡ oz/ft3 ≈ 7000100115396100000♠1.001153961 kg/m3

ounce (avoirdupois) per cubic inch oz/in3 ≡ oz/in3 ≈ 7003172999404399999♠1.729994044×103 kg/m3

ounce (avoirdupois) per gallon (imperial) oz/gal ≡ oz/gal ≈ 7000623602329100000♠6.236023291 kg/m3

ounce (avoirdupois) per gallon (US fluid) oz/gal ≡ oz/gal ≈ 7000748915170700000♠7.489151707 kg/m3

pound (avoirdupois) per cubic foot lb/ft3 ≡ lb/ft3 ≈ 7001160184633700000♠16.01846337 kg/m3

pound (avoirdupois) per cubic inch lb/in3 ≡ lb/in3 ≈ 7004276799047100000♠2.767990471×104 kg/m3

pound (avoirdupois) per gallon (imperial) lb/gal ≡ lb/gal ≈ 7001997763726600000♠99.77637266 kg/m3

pound (avoirdupois) per gallon (US fluid) lb/gal ≡ lb/gal ≈ 7002119826427300000♠119.8264273 kg/m3

slug per cubic foot slug/ft3 ≡ slug/ft3 ≈ 7002515378818400000♠515.3788184 kg/m3

Time[edit]

Time

Name of unit Symbol Definition Relation to SI units

Atomic unit of time au ≡ a0/(α·c) ≈ 6983241888425400000♠2.418884254×10−17 s

Callippic cycle   ≡ 441 mo (hollow) + 499 mo (full) = 76 a of 365.25 d = 7009239673600000000♠2.396736 Gs or 7009239837760000000♠2.3983776 Gs[note 1]

Century c ≡ 100 years (100 a) = 7009315569520000000♠3.1556952 Gs[note 2][note 3]

Day d = 24 h = 7003144000000000000♠1440 min = 7004864000000000000♠86.4 ks[note 3]

Day
Day
(sidereal) d ≡ Time
Time
needed for the Earth to rotate once around its axis, determined from successive transits of a very distant astronomical object across an observer's meridian (International Celestial Reference Frame) ≈ 7004861641000000000♠86.1641 ks

Decade dec ≡ 10 years (10 a) = 7008315569520000000♠315.569520 Ms[note 2][note 3]

Fortnight fn ≡ 2 wk = 7006120960000000000♠1.2096 Ms[note 3]

Helek

≡ ​1⁄7003108000000000000♠1080 h = 3.3 s

Hipparchic cycle   ≡ 4 Callippic cycles - 1 d = 7009959342400000000♠9.593424 Gs

Hour h ≡ 60 min = 7003360000000000000♠3.6 ks[note 3]

Jiffy j ≡ ​1⁄60 s = 16.6 ms

Jiffy (alternative) ja ≡ ​1⁄100 s = 10 ms

Ke (quarter of an hour)   ≡ ​1⁄4 h = ​1⁄96 d = 15 min = 900 s

Ke (traditional)   ≡ ​1⁄100 d = 14.4 min = 864 s

Lustre; Lustrum   ≡ 5 a of 365 d[note 4] = 7008157680000000000♠157.68 Ms

Metonic cycle; enneadecaeteris   ≡ 110 mo (hollow) + 125 mo (full) = 6940 d ≈ 19 a = 7008599616000000000♠599.616 Ms

Millennium   ≡ 7003100000000000000♠1000 years (7010315576000000000♠1000 a) = 7010315569520000000♠31.556952 Gs[note 2][note 3]

Milliday md ≡ ​1⁄7003100000000000000♠1000 d = 86.4 s

Minute min ≡ 60 s, due to leap seconds sometimes 59 s or 61 s, = 60 s[note 3]

Moment   ≡ 90 s = 90 s

Month
Month
(full) mo ≡ 30 d[26] = 7006259200000000000♠2.592×106 s[note 3]

Month
Month
(Greg. av.) mo = 7006262974600000000♠30.436875 d ≈ 7006262970000000000♠2.6297 Ms[note 3]

Month
Month
(hollow) mo ≡ 29 d[26] = 7006250560000000000♠2.5056 Ms[note 3]

Month
Month
(synodic) mo Cycle time of moon phases ≈ 7006255144288960000♠29.530589 d (average) ≈ 7006255100000000000♠2.551 Ms

Octaeteris   = 48 mo (full) + 48 mo (hollow) + 3 mo (full)[27][28] = 8 a of 365.25 d = 2922 d = 7008252460800000000♠252.4608 Ms[note 3]

Planck time   ≡ (​Gℏ⁄c5)​1⁄2 ≈ 6957135121186800000♠1.351211868×10−43 s

Second s Time
Time
of 7009919263177000000♠9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom at 0 K[10] (but other seconds are sometimes used in astronomy). Also that time it takes for light to travel a distance of 7008299792458000000♠299792458 metres. (SI base unit)

Shake   ≡ 10−8 s = 10 ns

Sigma   ≡ 10−6 s = 1 μs

Sothic cycle   ≡ 7003146100000000000♠1461 a of 365 d = 7014460740960000000♠460.74096 Ts

Svedberg S ≡ 10−13 s = 100 fs

Week wk ≡ 7 d = 168 h = 7005604800000000000♠10080 min = 7005604800000000000♠604.8 ks[note 3]

Year
Year
(common) a, y, or yr 365 d = 7007315360000000000♠31.536 Ms[note 3][note 3][29]

Year
Year
(Gregorian) a, y, or yr = 365.2425 d average, calculated from common years (365 d) plus leap years (366 d) on most years divisible by 4. See leap year for details. = 7007315569520000000♠31.556952 Ms[note 3]

Year
Year
(Julian) a, y, or yr = 365.25 d average, calculated from common years (365 d) plus one leap year (366 d) every four years = 7007315576000000000♠31.5576 Ms

Year
Year
(leap) a, y, or yr 366 d = 7007316224000000000♠31.6224 Ms[note 3][29]

Year
Year
(mean tropical) a, y, or yr Conceptually, the length of time it takes for the Sun to return to the same position in the cycle of seasons, [Converter 1] approximately 7002365242190000000♠365.24219 d, each day being 7004864000000000000♠86400 SI seconds[30] ≈ 7007315569250000000♠31.556925 Ms

Year
Year
(sidereal) a, y, or yr ≡ Time
Time
taken for Sun to return to the same position with respect to the stars of the celestial sphere, approximately 7007315581497632000♠365.256363 d ≈ 7007315581497632000♠31.5581497632 Ms

Notes:

^ see Callippic cycle for explanation of the differences ^ a b c This is based on the average Gregorian year. See above for definition of year lengths. ^ a b c d e f g h i j k l m n o p Where UTC
UTC
is observed, the length of this unit may increase or decrease depending on the number of leap seconds which occur during the time interval in question. ^ The length of ancient lustral cycles was not constant; see Lustrum for more details

Frequency[edit]

Frequency

Name of unit Symbol Definition Relation to SI units

hertz (SI unit) Hz ≡ Number of cycles per second = 1 Hz = 1/s

revolutions per minute rpm ≡ One unit rpm equals one rotation completed around a fixed axis in one minute of time. ≈ 6997104719754999999♠0.104719755 rad/s

Speed
Speed
or velocity[edit]

Speed

Name of unit Symbol Definition Relation to SI units

foot per hour fph ≡ 1 ft/h = 8.46×10−5 m/s

foot per minute fpm ≡ 1 ft/min = 6997508000000000000♠5.08×10−3 m/s

foot per second fps ≡ 1 ft/s = 6999304800000000000♠3.048×10−1 m/s

furlong per fortnight   ≡ furlong/fortnight ≈ 6996166309500000000♠1.663095×10−4 m/s

inch per hour iph ≡ 1 in/h = 7.05×10−6 m/s

inch per minute ipm ≡ 1 in/min = 4.23×10−4 m/s

inch per second ips ≡ 1 in/s = 6998254000000000000♠2.54×10−2 m/s

kilometre per hour km/h ≡ 1 km/h = 2.7×10−1 m/s

knot kn ≡ 1 nmi/h = 1.852 km/h = 0.514 m/s

knot (Admiralty) kn ≡ 1 NM (Adm)/h = 6999514773333333333♠1.853184 km/h[citation needed] = 6999514769999999999♠0.514773 m/s

mach number M Ratio of the speed to the speed of sound[note 1] in the medium (unitless). ≈ 340 to 295 m/s

metre per second (SI unit) m/s ≡ 1 m/s = 1 m/s

mile per hour mph ≡ 1 mi/h = 6999447040000000000♠0.44704 m/s

mile per minute mpm ≡ 1 mi/min = 7001268223999999999♠26.8224 m/s

mile per second mps ≡ 1 mi/s = 7003160934400000000♠1609.344 m/s

speed of light in vacuum c ≡ 7008299792458000000♠299792458 m/s = 7008299792458000000♠299792458 m/s

speed of sound in air s 7003122500000000000♠1225 to 7002295000000000000♠1062 km/h (761–660 mph or 661–574 kn)[note 1] ≈ 7002340000000000000♠340 to 295 m/s

Note

^ a b The speed of sound varies especially with temperature and pressure from about 7002340277777777777♠1225 km/h (761 mph or 661 kn) in air at sea level to about 7002295000000000000♠1062 km/h (660 mph or 570 kn) at jet altitudes (12200 m or 40000 ft).[31]

A velocity consists of a speed combined with a direction; the speed part of the velocity takes units of speed. Flow (volume)[edit]

Flow

Name of unit Symbol Definition Relation to SI units

cubic foot per minute CFM[citation needed] ≡ 1 ft3/min = 6996471947443200000♠4.719474432×10−4 m3/s

cubic foot per second ft3/s ≡ 1 ft3/s = 6998283168465920000♠0.028316846592 m3/s

cubic inch per minute in3/min ≡ 1 in3/min = 7000273117700000000♠2.7311773×10−7 m3/s

cubic inch per second in3/s ≡ 1 in3/s = 6995163870640000000♠1.6387064×10−5 m3/s

cubic metre per second (SI unit) m3/s ≡ 1 m3/s = 1 m3/s

gallon (US fluid) per day GPD[citation needed] ≡ 1 gal/d = 7000438126363000000♠4.381263638×10−8 m3/s

gallon (US fluid) per hour GPH[citation needed] ≡ 1 gal/h = 7000105150327000000♠1.051503273×10−6 m3/s

gallon (US fluid) per minute GPM[citation needed] ≡ 1 gal/min = 6995630901964000000♠6.30901964×10−5 m3/s

litre per minute LPM[citation needed] ≡ 1 L/min = 1.6×10−5 m3/s

Acceleration[edit]

Acceleration

Name of unit Symbol Definition Relation to SI units

foot per hour per second fph/s ≡ 1 ft/(h·s) = 8.46×10−5 m/s2

foot per minute per second fpm/s ≡ 1 ft/(min·s) = 6997508000000000000♠5.08×10−3 m/s2

foot per second squared fps2 ≡ 1 ft/s2 = 6999304800000000000♠3.048×10−1 m/s2

gal; galileo Gal ≡ 1 cm/s2 = 10−2 m/s2

inch per minute per second ipm/s ≡ 1 in/(min·s) = 4.23×10−4 m/s2

inch per second squared ips2 ≡ 1 in/s2 = 6998254000000000000♠2.54×10−2 m/s2

knot per second kn/s ≡ 1 kn/s ≈ 5.14×10−1 m/s2

metre per second squared (SI unit) m/s2 ≡ 1 m/s2 = 1 m/s2

mile per hour per second mph/s ≡ 1 mi/(h·s) = 6999447040000000000♠4.4704×10−1 m/s2

mile per minute per second mpm/s ≡ 1 mi/(min·s) = 26.8224 m/s2

mile per second squared mps2 ≡ 1 mi/s2 = 7003160934400000000♠1.609344×103 m/s2

standard gravity ɡ0 ≡ 7000980665000000000♠9.80665 m/s2 = 7000980665000000000♠9.80665 m/s2

Force[edit]

Force

Name of unit Symbol Definition Relation to SI units

atomic unit of force

≡ ​me·α2·c2⁄a0 ≈ 6992823872206000000♠8.23872206×10−8 N[32]

dyne (cgs unit) dyn ≡ g·cm/s2 = 10−5 N

kilogram-force; kilopond; grave-force kgf; kp; Gf ≡ ɡ0 × 1 kg = 7000980665000000000♠9.80665 N

kip; kip-force kip; kipf; klbf ≡ ɡ0 × 7002453592370000000♠1000 lb = 7003444822161526049♠4.4482216152605×103 N

milligrave-force, gravet-force mGf; gf ≡ ɡ0 × 1 g = 6997980665000000000♠9.80665 mN

long ton-force tnf[citation needed] ≡ ɡ0 × 1 long ton = 7003996401641818352♠9.96401641818352×103 N

newton (SI unit) N A force capable of giving a mass of one kilogram an acceleration of one metre per second per second.[33] = 1 N = 1 kg·m/s2

ounce-force ozf ≡ ɡ0 × 1 oz = 6999278013850953781♠0.27801385095378125 N

pound-force lbf ≡ ɡ0 × 1 lb = 7000444822161526049♠4.4482216152605 N

poundal pdl ≡ 1 lb·ft/s2 = 6999138254954376000♠0.138254954376 N

short ton-force tnf[citation needed] ≡ ɡ0 × 1 short ton = 7003889644323052099♠8.896443230521×103 N

sthene (mts unit) sn ≡ 1 t·m/s2 = 103 N

See also: Conversion between weight (force) and mass Pressure
Pressure
or mechanical stress[edit]

Pressure

Name of unit Symbol Definition Relation to SI units

atmosphere (standard) atm

≡ 7005101325000000000♠101325 Pa[34]

atmosphere (technical) at ≡ 1 kgf/cm2 = 7004980665000000000♠9.80665×104 Pa[34]

bar bar

≡ 105 Pa

barye (cgs unit)   ≡ 1 dyn/cm2 = 0.1 Pa

centimetre of mercury cmHg ≡ 7004135951000000000♠13595.1 kg/m3 × 1 cm × ɡ0 ≈ 7003133322000000000♠1.33322×103 Pa[34]

centimetre of water (4 °C) cmH2O ≈ 999.972 kg/m3 × 1 cm × ɡ0 ≈ 7001980638000000000♠98.0638 Pa[34]

foot of mercury (conventional) ftHg ≡ 7004135951000000000♠13595.1 kg/m3 × 1 ft × ɡ0 ≈ 7004406366599999999♠4.063666×104 Pa[34]

foot of water (39.2 °F) ftH2O ≈ 999.972 kg/m3 × 1 ft × ɡ0 ≈ 7003298898000000000♠2.98898×103 Pa[34]

inch of mercury (conventional) inHg ≡ 7004135951000000000♠13595.1 kg/m3 × 1 in × ɡ0 ≈ 7003338638899999999♠3.386389×103 Pa[34]

inch of water (39.2 °F) inH2O ≈ 999.972 kg/m3 × 1 in × ɡ0 ≈ 7002249082000000000♠249.082 Pa[34]

kilogram-force per square millimetre kgf/mm2 ≡ 1 kgf/mm2 = 7006980665000000000♠9.80665×106 Pa[34]

kip per square inch ksi ≡ 1 kipf/sq in ≈ 7006689475700000000♠6.894757×106 Pa[34]

long ton per square foot   ≡ 1 long ton × ɡ0 / 1 sq ft ≈ 7005107251780115950♠1.0725178011595×105 Pa

micrometre of mercury μmHg ≡ 7004135951000000000♠13595.1 kg/m3 × 1 μm × ɡ0 ≈ 0.001 torr ≈ 6999133322400000000♠0.1333224 Pa[34]

millimetre of mercury mmHg ≡ 7004135951000000000♠13595.1 kg/m3 × 1 mm × ɡ0 ≈ 1 torr ≈ 7002133322399999999♠133.3224 Pa[34]

millimetre of water (3.98 °C) mmH2O ≈ 999.972 kg/m3 × 1 mm × ɡ0 = 6999999972000000000♠0.999972 kgf/m2 = 7000980638000000000♠9.80638 Pa

pascal (SI unit) Pa ≡ N/m2 = kg/(m·s2) = 1 Pa[35]

pièze (mts unit) pz ≡ 7003100000000000000♠1000 kg/m·s2 = 7003100000000000000♠103 Pa = 1 kPa

pound per square foot psf ≡ 1 lbf/ft2 ≈ 7001478802600000000♠47.88026 Pa[34]

pound per square inch psi ≡ 1 lbf/in2 ≈ 7003689475700000000♠6.894757×103 Pa[34]

poundal per square foot pdl/sq ft ≡ 1 pdl/sq ft ≈ 7000148816400000000♠1.488164 Pa[34]

short ton per square foot   ≡ 1 short ton × ɡ0 / 1 sq ft ≈ 7004957605180000000♠9.5760518×104 Pa

torr torr ≡ ​7005101325000000000♠101325⁄760 Pa ≈ 7002133322399999999♠133.3224 Pa[34]

Torque
Torque
or moment of force[edit]

Torque

Name of unit Symbol Definition Relation to SI units

foot-pound force ft·lbf ≡ ɡ0 × 1 lb × 1 ft = 7000135581794833140♠1.3558179483314004 N⋅m

foot-poundal ft·pdl ≡ 1 lb·ft2/s2 = 6998421401100938048♠4.21401100938048×10−2 N⋅m

inch-pound force in·lbf ≡ ɡ0 × 1 lb × 1 in = 6999112984829027616♠0.1129848290276167 N⋅m

metre kilogram-force m·kgf ≡ ɡ0 × N × m = 7000980665000000000♠9.80665 N⋅m

Newton metre
Newton metre
(SI unit) N·m ≡ N × m = kg·m2/s2 = 7000100000000000000♠1 N⋅m

Energy[edit]

Energy

Name of unit Symbol Definition Relation to SI units

barrel of oil equivalent boe ≈ 7006580000000000000♠5.8×106 BTU59 °F ≈ 7009612000000000000♠6.12×109 J

British thermal unit (ISO) BTUISO ≡ 7003105450000000000♠1.0545×103 J = 7003105450000000000♠1.0545×103 J

British thermal unit (International Table) BTUIT

= 7003105505585262000♠1.05505585262×103 J

British thermal unit (mean) BTUmean

≈ 7003105587000000000♠1.05587×103 J

British thermal unit (thermochemical) BTUth

≈ 7003105434999999999♠1.054350×103 J

British thermal unit (39 °F) BTU39 °F

≈ 7003105966999999999♠1.05967×103 J

British thermal unit (59 °F) BTU59 °F ≡ 7003105480400000000♠1.054804×103 J = 7003105480400000000♠1.054804×103 J

British thermal unit (60 °F) BTU60 °F

≈ 7003105468000000000♠1.05468×103 J

British thermal unit (63 °F) BTU63 °F

≈ 7003105459999999999♠1.0546×103 J

calorie (International Table) calIT ≡ 7000418680000000000♠4.1868 J = 7000418680000000000♠4.1868 J

calorie (mean) calmean ​1⁄100 of the energy required to warm one gram of air-free water from 0 °C to 100 °C at a pressure of 1 atm ≈ 7000419001999999999♠4.19002 J

calorie (thermochemical) calth ≡ 4.184 J = 7000418400000000000♠4.184 J

Calorie
Calorie
(US; FDA) Cal ≡ 1 kcal = 7003418400000000000♠1000 cal = 7003418400000000000♠4184 J

calorie (3.98 °C) cal3.98 °C

≈ 7000420450000000000♠4.2045 J

calorie (15 °C) cal15 °C ≡ 4.1855 J = 7000418550000000000♠4.1855 J

calorie (20 °C) cal20 °C

≈ 7000418190000000000♠4.1819 J

Celsius
Celsius
heat unit (International Table) CHUIT ≡ 1 BTUIT × 1 K/°R = 7003189910053471600♠1.899100534716×103 J

cubic centimetre of atmosphere; standard cubic centimetre cc atm; scc ≡ 1 atm × 1 cm3 = 6999101325000000000♠0.101325 J

cubic foot of atmosphere; standard cubic foot cu ft atm; scf ≡ 1 atm × 1 ft3 = 7003286920448093440♠2.8692044809344×103 J

cubic foot of natural gas   ≡ 7003100000000000000♠1000 BTUIT = 7006105505585262000♠1.05505585262×106 J

cubic yard of atmosphere; standard cubic yard cu yd atm; scy ≡ 1 atm × 1 yd3 = 7004774685209852288♠77.4685209852288×103 J

electronvolt eV ≡ e × 1 V ≈ 6981160217656499999♠1.602176565(35)×10−19 J

erg (cgs unit) erg ≡ 1 g·cm2/s2 = 10−7 J

foot-pound force ft lbf ≡ ɡ0 × 1 lb × 1 ft = 7000135581794833140♠1.3558179483314004 J

foot-poundal ft pdl ≡ 1 lb·ft2/s2 = 6998421401100938048♠4.21401100938048×10−2 J

gallon-atmosphere (imperial) imp gal atm ≡ 1 atm × 1 gal (imp) = 7002460632569250000♠460.63256925 J

gallon-atmosphere (US) US gal atm ≡ 1 atm × 1 gal (US) = 7002383556849013800♠383.5568490138 J

hartree, atomic unit of energy Eh ≡ me·α2·c2 (= 2 Ry) ≈ 6982435974400000000♠4.359744×10−18 J

horsepower-hour hp·h ≡ 1 hp × 1 h = 7006268451953769617♠2.684519537696172792×106 J

inch-pound force in lbf ≡ ɡ0 × 1 lb × 1 in = 6999112984829027616♠0.1129848290276167 J

joule (SI unit) J The work done when a force of one newton moves the point of its application a distance of one metre in the direction of the force.[33] = 1 J = 1 m·N = 1 kg·m2/s2 = 1 C·V = 1 W·s

kilocalorie; large calorie kcal; Cal ≡ 7003100000000000000♠1000 calIT = 7003418680000000000♠4.1868×103 J

kilowatt-hour; Board of Trade Unit kW·h; B.O.T.U. ≡ 1 kW × 1 h = 7006360000000000000♠3.6×106 J

litre-atmosphere l atm; sl ≡ 1 atm × 1 L = 7002101325000000000♠101.325 J

quad   ≡ 1015 BTUIT = 7018105505585262000♠1.05505585262×1018 J

rydberg Ry ≡ R∞·ℎ·c ≈ 6982217987200000000♠2.179872×10−18 J

therm (E.C.)   ≡ 7005100000000000000♠100000 BTUIT = 7008105505585262000♠105.505585262×106 J

therm (US)   ≡ 7005100000000000000♠100000 BTU59 °F = 7008105480400000000♠105.4804×106 J

thermie th ≡ 1 McalIT = 7006418680000000000♠4.1868×106 J

ton of coal equivalent TCE ≡ 7 Gcalth = 7010292880000000000♠29.288×109 J

tonne of oil equivalent toe ≡ 10 GcalIT = 7010418680000000000♠41.868×109 J

ton of TNT tTNT ≡ 1 Gcalth = 7009418400000000000♠4.184×109 J

Power or heat flow rate[edit]

Power

Name of unit Symbol Definition Relation to SI units

atmosphere-cubic centimetre per minute atm ccm[citation needed] ≡ 1 atm × 1 cm3/min = 6997168875000000000♠1.68875×10−3 W

atmosphere-cubic centimetre per second atm ccs[citation needed] ≡ 1 atm × 1 cm3/s = 6999101325000000000♠0.101325 W

atmosphere-cubic foot per hour atm cfh[citation needed] ≡ 1 atm × 1 cu ft/h = 6999797001247040000♠0.79700124704 W

atmosphere-cubic foot per minute atm cfm[citation needed] ≡ 1 atm × 1 cu ft/min = 7001478200746822400♠47.82007468224 W

atmosphere-cubic foot per second atm cfs[citation needed] ≡ 1 atm × 1 cu ft/s = 7003286920448093440♠2.8692044809344×103 W

BTU (International Table) per hour BTUIT/h ≡ 1 BTUIT/h ≈ 6999293071000000000♠0.293071 W

BTU (International Table) per minute BTUIT/min ≡ 1 BTUIT/min ≈ 7001175842640000000♠17.584264 W

BTU (International Table) per second BTUIT/s ≡ 1 BTUIT/s = 7003105505585262000♠1.05505585262×103 W

calorie (International Table) per second calIT/s ≡ 1 calIT/s = 7000418680000000000♠4.1868 W

erg per second erg/s ≡ 1 erg/s = 6993100000000000000♠10−7 W

foot-pound-force per hour ft·lbf/h ≡ 1 ft lbf/h ≈ 6996376616100000000♠3.766161×10−4 W

foot-pound-force per minute ft·lbf/min ≡ 1 ft lbf/min = 6998225969658055233♠2.259696580552334×10−2 W

foot-pound-force per second ft·lbf/s ≡ 1 ft lbf/s = 7000135581794833140♠1.3558179483314004 W

horsepower (boiler) hp ≈ 34.5 lb/h × 970.3 BTUIT/lb ≈ 7003980950000000000♠9809.5 W[36]

horsepower (European electrical) hp ≡ 75 kp·m/s = 7002736000000000000♠736 W[citation needed]

horsepower (electrical) hp ≡ 746 W = 7002746000000000000♠746 W[36]

horsepower (mechanical) hp ≡ 550 ft·lbf/s[36] = 7002745699871582270♠745.69987158227022 W

horsepower (metric) hp or PS ≡ 75 m·kgf/s = 7002735498750000000♠735.49875 W[36]

litre-atmosphere per minute L·atm/min ≡ 1 atm × 1 L/min = 7000168875000000000♠1.68875 W

litre-atmosphere per second L·atm/s ≡ 1 atm × 1 L/s = 7002101325000000000♠101.325 W

lusec lusec ≡ 1 L·µmHg/s [18] ≈ 6996133300000000000♠1.333×10−4 W

poncelet p ≡ 100 m·kgf/s = 7002980665000000000♠980.665 W

square foot equivalent direct radiation sq ft EDR ≡ 240 BTUIT/h ≈ 7001703370570000000♠70.337057 W

ton of air conditioning   ≡ 7002907184740000000♠2000 lb of ice melted / 24 h ≈ 7003350400000000000♠3504 W

ton of refrigeration (imperial)   ≡ 7003101604690880000♠2240 lb × iceIT / 24 h: iceIT = 144 °F × 2326 J/kg·°F ≈ 7003393887500000000♠3.938875×103 W

ton of refrigeration (IT)   ≡ 7002907184740000000♠2000 lb × iceIT / 24 h: iceIT = 144 °F × 2326 J/kg·°F ≈ 7003351685299999999♠3.516853×103 W

watt (SI unit) W The power which in one second of time gives rise to one joule of energy.[33] = 7000100000000000000♠1 W = 1 J/s = 1 N·m/s = 1 kg·m2/s3

Action[edit]

Action

Name of unit Symbol Definition Relation to SI units

atomic unit of action au ≡ ℏ ≡ ​ℎ⁄2π ≈ 6966105457168000000♠1.05457168×10−34 J·s[37]

Dynamic viscosity[edit]

Dynamic viscosity

Name of unit Symbol Definition Relation to SI units

pascal second (SI unit) Pa·s ≡ N·s/m2, kg/(m·s) = 1 Pa·s

poise (cgs unit) P ≡ 1 barye·s = 0.1 Pa·s

pound per foot hour lb/(ft·h) ≡ 1 lb/(ft·h) ≈ 6996413378900000000♠4.133789×10−4 Pa·s

pound per foot second lb/(ft·s) ≡ 1 lb/(ft·s) ≈ 7000148816400000000♠1.488164 Pa·s

pound-force second per square foot lbf·s/ft2 ≡ 1 lbf·s/ft2 ≈ 7001478802600000000♠47.88026 Pa·s

pound-force second per square inch lbf·s/in2 ≡ 1 lbf·s/in2 ≈ 7003689475700000000♠6894.757 Pa·s

Kinematic viscosity[edit]

Kinematic viscosity

Name of unit Symbol Definition Relation to SI units

square foot per second ft2/s ≡ 1 ft2/s = 6998929030400000000♠0.09290304 m2/s

square metre per second (SI unit) m2/s ≡ 1 m2/s = 1 m2/s

stokes (cgs unit) St ≡ 1 cm2/s = 10−4 m2/s

Electric current[edit]

Electric current

Name of unit Symbol Definition Relation to SI units

ampere (SI base unit) A ≡ The constant current needed to produce a force of 2 ×10−7 newton per metre between two straight parallel conductors of infinite length and negligible circular cross-section placed one metre apart in a vacuum.[10] = 1 A = 1 C/s

electromagnetic unit; abampere (cgs unit) abamp ≡ 10 A = 10 A

esu per second; statampere (cgs unit) esu/s ≡ ​0.1 A·m/s⁄c ≈ 6990333564100000000♠3.335641×10−10 A

Electric charge[edit]

Electric charge

Name of unit Symbol Definition Relation to SI units

abcoulomb; electromagnetic unit (cgs unit) abC; emu ≡ 10 C = 10 C

atomic unit of charge au ≡ e ≈ 6981160217646200000♠1.602176462×10−19 C

coulomb C ≡ The amount of electricity carried in one second of time by one ampere of current.[33] = 1 C = 1 A·s

faraday F ≡ 1 mol × NA·e ≈ 7004964853383000000♠96485.3383 C

milliampere hour mA·h ≡ 0.001 A × 1 h = 3.6 C

statcoulomb; franklin; electrostatic unit (cgs unit) statC; Fr; esu ≡ ​0.1 A·m⁄c ≈ 6990333564100000000♠3.335641×10−10 C

Electric dipole[edit]

Electric dipole

Name of unit Symbol Definition Relation to SI units

atomic unit of electric dipole moment ea0   ≈ 6970847835281000000♠8.47835281×10−30 C·m[38]

coulomb meter C·m   = 1 C · 1 m

debye D = 10−10 esu·Å = 6970333564095000000♠3.33564095×10−30 C·m[39]

Electromotive force, electric potential difference[edit]

Voltage, electromotive force

Name of unit Symbol Definition Relation to SI units

abvolt (cgs unit) abV ≡ 10−8 V = 10−8 V

statvolt (cgs unit) statV ≡ c·(1 μJ/A·m) = 7002299792458000000♠299.792458 V

volt (SI unit) V The difference in electric potential across two points along a conducting wire carrying one ampere of constant current when the power dissipated between the points equals one watt.[33] = 1 V = 1 W/A = 1 kg·m2/(A·s3)

Electrical resistance[edit]

Electrical resistance

Name of unit Symbol Definition Relation to SI units

ohm (SI unit) Ω The resistance between two points in a conductor when one volt of electric potential difference, applied to these points, produces one ampere of current in the conductor.[33] = 1 Ω = 1 V/A = 1 kg·m2/(A2·s3)

Capacitance[edit]

Capacitor's ability to store charge

Name of unit Symbol Definition Relation to SI units

farad (SI unit) F The capacitance between two parallel plates that results in one volt of potential difference when charged by one coulomb of electricity.[33] = 1 F = 1 C/V = 1 A2·s4/(kg·m2)

Magnetic flux[edit]

magnetic flux

Name of unit Symbol Definition Relation to SI units

maxwell (CGS unit) Mx ≡ 10−8 Wb[36] = 10−8 Wb

weber (SI unit) Wb Magnetic flux
Magnetic flux
which, linking a circuit of one turn, would produce in it an electromotive force of 1 volt if it were reduced to zero at a uniform rate in 1 second.[33] = 1 Wb = 1 V·s = 1 kg·m2/(A·s2)

Magnetic flux
Magnetic flux
density[edit]

What physicists call Magnetic field
Magnetic field
is called Magnetic flux
Magnetic flux
density by electrical engineers and magnetic induction by applied mathematicians and electrical engineers.

Name of unit Symbol Definition Relation to SI units

gauss (CGS unit) G ≡ Mx/cm2 = 10−4 T = 10−4 T [40]

tesla (SI unit) T ≡ Wb/m2 = 1 T = 1 Wb/m2 = 1 kg/(A·s2)

Inductance[edit]

Inductance

Name of unit Symbol Definition Relation to SI units

henry (SI unit) H The inductance of a closed circuit that produces one volt of electromotive force when the current in the circuit varies at a uniform rate of one ampere per second.[33] = 1 H = 1 Wb/A = 1 kg·m2/(A·s)2

Temperature[edit] Further information: Conversion of units
Conversion of units
of temperature

Temperature

Name of unit Symbol Definition Relation to SI units

degree Celsius °C [°C] ≡ [K] − 273.15 [K] ≡ [°C] + 273.15

degree Delisle °De

[K] = 373.15 − [°De] × ​2⁄3

degree Fahrenheit °F [°F] ≡ [°C] × ​9⁄5 + 32 [K] ≡ ([°F] + 459.67) × ​5⁄9

degree Newton °N

[K] = [°N] × ​100⁄33 + 273.15

degree Rankine °R; [°R] ≡ [K] × ​9⁄5 [K] ≡ [°R] × 5/9

degree Réaumur °Ré

[K] = [°Ré] × ​5⁄4 + 273.15

degree Rømer °Rø

[K] = ([°Rø] − 7.5) × ​40⁄21 + 273.15

Regulo Gas Mark GM; [°F] ≡ [GM] × 25 + 300 [K] ≡ [GM] × ​125⁄9 + 422.038

kelvin (SI base unit) K ≡ ​1⁄273.16 of the thermodynamic temperature of the triple point of water.[10] ≡ 1 K

Information entropy[edit]

Information entropy

Name of unit Symbol Definition Relation to SI units Relation to bits

natural unit of information; nip; nepit nat

shannon; bit Sh; bit; b ≡ ln(2) × nat ≈ 6999693147000000000♠0.693147 nat = 1 bit

hartley; ban Hart; ban ≡ ln(10) × nat ≈ 7000230258500000000♠2.302585 nat

nibble

≡ 4 bits

= 22 bit

byte B ≡ 8 bits

= 23 bit

kilobyte (decimal) kB ≡ 7003100000000000000♠1000 B

= 7003800000000000000♠8000 bit

kilobyte (kibibyte) KB; KiB ≡ 7003102400000000000♠1024 B

= 213 bit = 7003819200000000000♠8192 bit

Modern standards (such as ISO 80000) prefer the shannon to the bit as a unit for a quantity of information entropy, whereas the (discrete) storage space of digital devices is measured in bits. Thus, uncompressed redundant data occupy more than one bit of storage per shannon of information entropy. The multiples of a bit listed above are usually used with this meaning. Luminous intensity[edit] The candela is the preferred nomenclature for the SI unit.

Luminous intensity

Name of unit Symbol Definition Relation to SI units

candela (SI base unit); candle cd The luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540×1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.[10] = 1 cd

candlepower (new) cp ≡ cd The use of candlepower as a unit is discouraged due to its ambiguity. = 1 cd

candlepower (old, pre-1948) cp Varies and is poorly reproducible.[41] Approximately 0.981 cd.[18] ≈ 0.981 cd

Luminance[edit]

Luminance

Name of unit Symbol Definition Relation to SI units

candela per square foot cd/ft2 ≡ cd/ft2 ≈ 7001107639104170000♠10.763910417 cd/m2

candela per square inch cd/in2 ≡ cd/in2 ≈ 7003155000310000000♠1550.0031 cd/m2

candela per square metre (SI unit); nit (deprecated[18]) cd/m2 ≡ cd/m2 = 1 cd/m2

footlambert fL ≡ (1/π) cd/ft2 ≈ 7000342625909960000♠3.4262590996 cd/m2

lambert L ≡ (104/π) cd/m2 ≈ 7003318309886180000♠3183.0988618 cd/m2

stilb (CGS unit) sb ≡ 104 cd/m2 = 104 cd/m2

Luminous flux[edit]

Luminous flux

Name of unit Symbol Definition Relation to SI units

lumen (SI unit) lm ≡ cd·sr = 1 lm = 1 cd·sr

Illuminance[edit]

Illuminance

Name of unit Symbol Definition Relation to SI units

footcandle; lumen per square foot fc ≡ lm/ft2 = 7001107639104170000♠10.763910417 lx

lumen per square inch lm/in2 ≡ lm/in2 ≈ 7003155000310000000♠1550.0031 lx

lux (SI unit) lx ≡ lm/m2 = 1 lx = 1 lm/m2

phot (CGS unit) ph ≡ lm/cm2 = 104 lx

Radiation – source activity[edit]

Radioactivity

Name of unit Symbol Definition Relation to SI units

becquerel (SI unit) Bq ≡ Number of disintegrations per second = 1 Bq = 1/s

curie Ci ≡ 7010370000000000000♠3.7×1010 Bq[42] = 7010370000000000000♠3.7×1010 Bq

rutherford (H) rd ≡ 1 MBq = 106 Bq

Although becquerel (Bq) and hertz (Hz) both ultimately refer to the same SI base unit
SI base unit
(s−1), Hz is used only for periodic phenomena (ie repetitions at regular intervals), and Bq is only used for stochastic processes (ie at random intervals) associated with radioactivity.[43] Radiation – exposure[edit]

Radiation - exposure

Name of unit Symbol Definition Relation to SI units

roentgen R 1 R ≡ 6996258000000000000♠2.58×10−4 C/kg[36] = 6996258000000000000♠2.58×10−4 C/kg

The roentgen is not an SI unit and the NIST strongly discourages its continued use.[44] Radiation – absorbed dose[edit]

Radiation - absorbed dose

Name of unit Symbol Definition Relation to SI units

gray (SI unit) Gy ≡ 1 J/kg = 1 m2/s2 [45] = 1 Gy

rad rad ≡ 0.01 Gy[36] = 0.01 Gy

Radiation – equivalent dose[edit]

Radiation - equivalent dose

Name of unit Symbol Definition Relation to SI units

Röntgen equivalent man rem ≡ 0.01 Sv = 0.01 Sv

sievert (SI unit) Sv ≡ 1 J/kg[43] = 1 Sv

Although the definitions for sievert (Sv) and gray (Gy) would seem to indicate that they measure the same quantities, this is not the case. The effect of receiving a certain dose of radiation (given as Gy) is variable and depends on many factors, thus a new unit was needed to denote the biological effectiveness of that dose on the body; this is known as the equivalent dose and is shown in Sv. The general relationship between absorbed dose and equivalent dose can be represented as

H = Q · D

where H is the equivalent dose, D is the absorbed dose, and Q is a dimensionless quality factor. Thus, for any quantity of D measured in Gy, the numerical value for H measured in Sv may be different.[46] See also[edit]

Accuracy and precision Conversion of units
Conversion of units
of temperature English units False precision Imperial units International System of Units Mesures usuelles Metric prefix
Metric prefix
(e.g. "kilo-" prefix) Metric system Natural units Rounding Significant figures United States customary units Units (software) Units conversion by factor-label Units of measurement

Notes and references[edit]

^ Béla Bodó; Colin Jones (26 June 2013). Introduction to Soil Mechanics. John Wiley & Sons. pp. 9–. ISBN 978-1-118-55388-6.  ^ "Identity property of multiplication". Retrieved 2015-09-09.  ^ jobs (September 14, 2012). "The astronomical unit gets fixed : Nature News & Comment". Nature.com. doi:10.1038/nature.2012.11416. Retrieved August 31, 2013.  ^ "NIST Reference on Constants, Units, and Uncertainty."(2010). National Institute of Standards and Technology. Retrieved October 17, 2014. ^ a b U.S. National Institute of Standards and Technology
National Institute of Standards and Technology
Handbook 44 Appendix C - General Tables of Units of Measurement 2013 Edition ^ a b c d e f g h i j k l m n Lide, D. (Ed.). (1990). Handbook of Chemistry and Physics (71st ed). Boca Raton, FL: CRC Press. Section 1. ^ a b National Bureau of Standards. (June 30, 1959). Refinement of values for the yard and the pound. Federal Register, viewed September 20, 2006 at National Geodetic Survey web site. ^ The International Astronomical Union and Astronomical Units ^ Klein, Herbert Arthur. (1988). The Science of Measurement: a Historical Survey. Mineola, NY: Dover Publications 0-4862-5839-4. ^ a b c d e f The International System of Units, Section 2.1 (8 ed.), Bureau International des Poids et Mesures, 2006, archived from the original on October 1, 2009, retrieved August 26, 2009  ^ International System of Units, Archived August 21, 2008, at the Wayback Machine. 8th ed. (2006), Bureau International des Poids et Mesures, Section 4.1 Table 8. ^ Cox, Arthur N., ed. (2000). Allen's Astrophysical Quantities (4th ed.). New York: AIP Press / Springer. Bibcode:2000asqu.book.....C. ISBN 0387987460.  ^ Binney, James; Tremaine, Scott (2008). Galactic Dynamics (2nd ed.). Princeton, NJ: Princeton University Press. Bibcode:2008gady.book.....B. ISBN 978-0-691-13026-2.  ^ P. Kenneth Seidelmann, Ed. (1992). Explanatory Supplement to the Astronomical Almanac. Sausalito, CA: University Science Books. p. 716 and s.v. parsec in Glossary. ^ a b c Whitelaw, Ian. (2007). A Measure of All Things: The Story of Man and Measurement. New York: Macmillan 0-312-37026-1. p. 152. ^ a b De Vinne, Theodore Low (1900). The practice of typography: a treatise on the processes of type-making, the point system, the names, sizes, styles and prices of plain printing types 2nd ed. New York: The Century Co. p. 142–150. ^ Pasko, Wesley Washington (1894). American dictionary of printing and bookmaking. (1894). New York: Howard Lockwood. p. 521. ^ a b c d e f g h Rowlett, Russ (2005), How Many? A Dictionary of Units of Measurement  ^ Thompson, A. and Taylor, B.N. (2008). Guide for the Use of the International System of Units
International System of Units
(SI). National Institute of Standards and Technology Special
Special
Publication 811. p. 57. ^ a b c d e US Code of Federal Regulations, Title 21, Section 101.9, Paragraph (b)(5)(viii), archived from the original on August 13, 2009, retrieved August 29, 2009  ^ Barry N. Taylor, Ed.,NIST Special
Special
Publication 330: The International System of Units (SI) (2001 Edition), Washington: US Government Printing Office, 43,"The 12th Conference Generale des Poids et Mesures (CGPM)…declares that the word "litre" may be employed as a special name for the cubic decimetre". ^ a b [1] ^ CODATA Value: atomic unit of mass. (2010). National Institute of Standards and Technology. Retrieved 29 May 2015. ^ http://physics.nist.gov/cgi-bin/cuu/Value?tevj%7Csearch_for=electronvolt ^ The Swiss Federal Office for Metrology gives Zentner on a German language web page "Archived copy". Archived from the original on 2006-09-28. Retrieved 2006-10-09.  and quintal on the English translation of that page "Archived copy". Archived from the original on 2001-03-09. Retrieved 2006-10-09. ; the unit is marked "spécifiquement suisse !" ^ a b Pedersen O. (1983). "Glossary" in Coyne, G., Hoskin, M., and Pedersen, O. Gregorian Reform of the Calendar: Proceedings of the Vatican Conference to Commemorate its 400th Anniversary. Vatican Observatory. Available from Astrophysics Data System. ^ Richards, E.G. (1998), Mapping Time, Oxford University Press, pp. 94–95, ISBN 0-19-850413-6  ^ Steel, Duncan (2000), Marking Time, John Wiley & Sons, p. 46, ISBN 0-471-29827-1  ^ a b Richards, E. G. (2013). "Calendars" in S. E. Urban & P. K. Seidelmann, eds. Explanatory Supplement to the Astronomical Almanac. Mill Valley, CA: University Science Books. ^ Richards, E. G. (2013). "Calendars" in S. E. Urban & P. K. Seidelmann, eds. Explanatory Supplement to the Astronomical Almanac. Mill Valley, CA: University Science Books. p. 587. ^ Tom Benson. (2010.) "Mach Number" in Beginner's Guide to Aeronautics. NASA. ^ CODATA Value: atomic unit of force. (2006). National Institute of Standards and Technology. Retrieved September 14, 2008. ^ a b c d e f g h i Comité International des Poids et Mesures, Resolution 2, 1946, retrieved August 26, 2009  ^ a b c d e f g h i j k l m n o p Barry N. Taylor, (April 1995), Guide for the Use of the International System of Units
International System of Units
(SI) (NIST Special Publication 811), Washington, DC: US Government Printing Office, pp. 57–68. ^ Barry N. Taylor, (April 1995), Guide for the Use of the International System of Units
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Special
Publication 811), Washington, DC: US Government Printing Office, p. 5. ^ a b c d e f g NIST Guide to SI Units, Appendix B.9, retrieved August 27, 2009  ^ International System of Units, Archived July 16, 2012, at the Wayback Machine. 8th ed. (2006), Bureau International des Poids et Mesures, Section 4.1 Table 7. ^ The NIST Reference on Constants, Units, and Uncertainty, 2006, retrieved August 26, 2009  ^ Robert G. Mortimer Physical chemistry,Academic Press, 2000 ISBN 0-12-508345-9, page 677 ^ Standard for the Use of the International System of Units
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(SI): The Modern Metric System IEEE/ASTM SI 10-1997. (1997). New York and West Conshohocken, PA: Institute of Electrical and Electronics Engineers and American Society for Testing and Materials. Tables A.1 through A.5. ^ The NIST Reference on Constants, Units, and Uncertainty, retrieved August 28, 2009  ^ Ambler Thompson & Barry N. Taylor. (2008). Guide for the Use of the International System of Units
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Publication 811. Gaithersburg, MD: National Institute of Standards and Technology. p. 10. ^ a b The International System of Units, Section 2.2.2., Table 3 (8 ed.), Bureau International des Poids et Mesures, 2006, archived from the original on June 18, 2007, retrieved August 27, 2009  ^ The NIST Guide to the SI ( Special
Special
Publication 811), section 5.2, 2008, retrieved August 27, 2009  ^ Ambler Thompson & Barry N. Taylor. (2008). Guide for the Use of the International System of Units
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Special
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Notes

^ The technical definition of tropical year is the period of time for the ecliptic longitude of the Sun to increase 360 degrees. (Urban & Seidelmann 2013, Glossary, s.v. year, tropical)

External links[edit]

Wikibooks has a book on the topic of: FHSST Physics Units:How to Change Units

Wikivoyage has a travel guide for Metric and Imperial equivalents.

Statutory Instrument 1995 No. 1804 Units of measurement
Units of measurement
regulations 1995 From legislation.gov.uk How Many? A dictionary of units of measurement "NIST: Fundamental physical constants — Non-SI units" (PDF).  (35.7 KB) NIST Guide to SI Units Many conversion factors listed. The Unified Code for Units of Measure Units, Symbols, and Conversions XML Dictionary Units, Symbols, Exchange, Equations, Human Readable Units of Measurement Software at Curlie (based on DMOZ) Units of Measurement Online Conversion at Curlie (based on DMOZ)

v t e

Systems of measurement

Current

General

International System of Units
International System of Units
(SI) UK imperial system US customary units Myanmar Indian

Specific

Apothecaries' Avoirdupois Troy Astronomical Electrical Temperature

Natural

atomic geometrised Gaussian Lorentz–Heaviside Planck quantum chromodynamical Stoney

Background

Metric

Overview Introduction Outline History Metrication

UK/US

Overview Comparison Foot–pound–second (FPS)

Historic

Metric

metre–kilogram–second (MKS) metre–tonne–second (MTS) centimetre–gram–second (CGS) gravitational quadrant–eleventh-gram–second (QES) (hebdometre–undecimogramme–second (HUS))

Europe

Byzantine Cornish Cypriot Czech Danish Dutch English Estonian Finnish French (Trad. • Mesures usuelles) German Greek Hungary Icelandic Irish Scottish Italian Latvia Luxembourgian Maltese Norwegian Ottoman Polish Portuguese Romanian Russian Serbian Slovak Spanish Swedish Switzerland Welsh Winchester measure

Asia

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Africa

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North America

Costa Rican Cuban Haitian Honduran Mexico Nicaraguan Puerto Rican

South America

Argentine Brazilian Chilean Colombian Paraguayan Peruvian Uruguayan Venezuelan

Ancient

Arabic Biblical and Talmudic Egyptian Greek Hindu Indian Mesopotamian Persian Roman

List articles

Humorous (FFF system) Obsolete Unusual

Other

N-body Modulor

v t e

SI units

Authority: International System of Units
International System of Units
(BIPM)

Base units

ampere candela kelvin kilogram metre mole second

Derived units with special names

becquerel coulomb degree Celsius farad gray henry hertz joule katal lumen lux newton ohm pascal radian siemens sievert steradian tesla volt watt weber

Other accepted units

astronomical unit bar dalton day decibel degree of arc electronvolt hectare hour litre minute minute of arc neper second of arc tonne atomic units natural units

See also

Conversion of units Metric prefixes Proposed redefinitions Systems of measurement

.