1 E-7 m

The following are examples of orders of magnitude for different lengths.

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Overview

Detailed list

To help compare different orders of magnitude, the following list describes various lengths between $1.6 \times 10^$ metres and $10^$metres.

Subatomic scale

Atomic to cellular scale

Cellular to human scale

Human to astronomical scale

Astronomical scale

Less than 1 zeptometre

The ' ( SI symbol: ') is a unit of length in the metric system equal to .
To help compare different orders of magnitude, this section lists lengths shorter than 10⁻²¹ m (1 zm).

*1.6 × 10⁻⁵ quectometres (1.6 × 10⁻³⁵ metres) – the Planck length (Measures of distance shorter than this do not make physical sense, according to current theories of physics.)
*1 qm – 1 quectometre, the smallest named subdivision of the metre in the SI base unit of length, one nonillionth of a metre
*1 rm – 1 rontometre, a subdivision of the metre in the SI base unit of length, one octillionth of a metre
*10 rm – the length of one side of a square whose area is one shed, a unit of target cross section used in nuclear physics
*2 ym – the effective cross-section radius of 1 MeV neutrinos as measured by Clyde Cowan and Frederick Reines

1 zeptometre

The ' ( SI symbol: ') is a unit of length in the metric system equal to .
To help compare different orders of magnitude, this section lists lengths between 10⁻²¹ m and 10⁻²⁰ m (1 zm and 10 zm).

*2 zm – the upper bound for the width of a cosmic string in string theory.
*2 zm – radius of effective cross section for a 20 GeV neutrino scattering off a nucleon
*7 zm – radius of effective cross section for a 250 GeV neutrino scattering off a nucleon

10 zeptometres

To help compare different orders of magnitude, this section lists lengths between 10⁻²⁰ m and 10⁻¹⁹ m (10 zm and 100 zm).

100 zeptometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁹ m and 10⁻¹⁸ m (100 zm and 1 am).

*177 zm – de Broglie wavelength of protons at the Large Hadron Collider (7 TeV as of 2010)

1 attometre

The ' ( SI symbol: ') is a unit of length in the metric system equal to .
To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁸ m and 10⁻¹⁷ m (1 am and 10 am).

*1 am – sensitivity of the LIGO detector for gravitational waves
*1 am – upper limit for the size of quarks and electrons

10 attometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁷ m and 10⁻¹⁶ m (10 am and 100 am).

*10 am – range of the weak force

100 attometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁶ m and 10⁻¹⁵ m (100 am and 1 fm).

*100 am – all lengths shorter than this distance are not confirmed in terms of size
*850 am – approximate proton radius

1 femtometre

The ' ( SI symbol: ') is a unit of length in the metric system equal to .
In particle physics, this unit is more commonly called a , also with abbreviation "fm". To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁵ metres and 10⁻¹⁴ metres (1 femtometre and 10 fm).

*1 fm – diameter of a neutron, approximate range-limit of the color force carried between quarks by gluons
*1.5 fm – diameter of the scattering cross section of an 11 MeV proton with a target proton
*1.75 fm – the effective charge diameter of a proton
*2.81794 fm – classical electron radius
*3 fm – approximate range-limit of the nuclear binding force mediated by mesons
*7 fm – the radius of the effective scattering cross section for a gold nucleus scattering a 6 MeV alpha particle over 140 degrees

10 femtometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁴ m and 10⁻¹³ m (10 fm and 100 fm).

*1.75 to 15 fm – Diameter range of the atomic nucleus

100 femtometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹³ m and 10⁻¹² m (100 fm and 1 pm).

*570 fm – typical distance from the atomic nucleus of the two innermost electrons (electrons in the ''1s'' shell) in the uranium atom, the heaviest naturally-occurring atom

1 picometre

The ' ( SI symbol: ') is a unit of length in the metric system equal to ().
To help compare different orders of magnitude this section lists lengths between 10⁻¹² and 10⁻¹¹ m (1 pm and 10 pm).

*1 pm – distance between atomic nuclei in a white dwarf
*1 pm – reference value of particle displacement in acoustics
*2.4 pm – The Compton wavelength of an electron
*5 pm – shorter X-ray wavelengths (approx.)

10 picometres

To help compare different orders of magnitude this section lists lengths between 10⁻¹¹ and 10⁻¹⁰ m (10 pm and 100 pm).

*25 pm – approximate radius of a helium atom, the smallest neutral atom
*50 pm – radius of a hydrogen atom
*50 pm – bohr radius: approximate radius of a hydrogen atom
*~50 pm – best resolution of a high-resolution transmission electron microscope
*60 pm – radius of a carbon atom
*93 pm – length of a diatomic carbon molecule
*96 pm – H–O bond length in a water molecule

100 picometres

To help compare different orders of magnitude this section lists lengths between 10⁻¹⁰ and 10⁻⁹ m (100 pm and 1 nm; 1  Å and 10 Å).

*100 pm – 1 ångström
*100 pm – covalent radius of sulfur atom
*120 pm – van der Waals radius of a neutral hydrogen atom
*120 pm – radius of a gold atom
*126 pm – covalent radius of ruthenium atom
*135 pm – covalent radius of technetium atom
*150 pm – Length of a typical covalent bond ( C–C)
*153 pm – covalent radius of silver atom
*155 pm – covalent radius of zirconium atom
*175 pm – covalent radius of thulium atom
*200 pm – highest resolution of a typical electron microscope
*225 pm – covalent radius of caesium atom
*280 pm – Average size of the water molecule
*298 pm – radius of a caesium atom, calculated to be the largest atomic radius (except possibly francium)
*340 pm – thickness of single layer graphene
*356.68 pm – width of diamond unit cell
*403 pm – width of lithium fluoride unit cell
*500 pm – Width of protein α helix
*543 pm – silicon lattice spacing
*560 pm – width of sodium chloride unit cell
*700 pm – width of glucose molecule
*700 pm – diameter of a buckyball
*780 pm – mean width of quartz unit cell
*820 pm – mean width of ice unit cell
*900 pm – mean width of coesite unit cell

1 nanometre

The ' ( SI symbol: ') is a unit of length in the metric system equal to ().
To help compare different orders of magnitude, this section lists lengths between 10⁻⁹ and 10⁻⁸ m (1 nm and 10 nm).

*1 nm – diameter of a carbon nanotube
*1 nm – roughly the length of a sucrose molecule, calculated by Albert Einstein
*2.3 nm – length of a phospholipid
*2.3 nm – smallest gate oxide thickness in microprocessors
*3 nm – width of a DNA helix
*3 nm – flying height of the head of a hard disk
*3 nm – , the average half-pitch of a memory cell expected to be manufactured circa 2022
*3.4 nm – length of a DNA turn (10 bp)
*3.8 nm – size of an albumin molecule
*5 nm – size of the gate length of a 16 nm processor
*5 nm – , the average half-pitch of a memory cell manufactured circa 2019–2020
*6 nm – length of a phospholipid bilayer
*6–10 nm – thickness of cell membrane
*6.8 nm – width of a haemoglobin molecule
*7 nm – diameter of actin filaments
*7 nm – the average half-pitch of a memory cell manufactured circa 2018
*10 nm – Thickness of cell wall in Gram-negative bacteria

10 nanometres

To help compare different orders of magnitude this section lists lengths between 10⁻⁸ and 10⁻⁷ m (10 nm and 100 nm).

*10 nm – the average length of a nanowire
*10 nm – lower size of tobacco smokeAnnis, Patty J. October 1991. Kansas State University. ''Fine Particle POLLUTION''. Figure 1. (tobacco smoke: 10 to ; virus particles: 3 to 50 nm; bacteria: 30 to ; cooking oil smoke: 30 to ; wood smoke: 7 to )
*10 nm – the average half-pitch of a memory cell manufactured circa 2016 –2017
*13 nm – the length of the wavelength that is used for EUV lithography
*14 nm – Length of a porcine circovirus
*14 nm – the average half-pitch of a memory cell manufactured circa 2013
*15 nm – Length of an antibody
*18 nm – diameter of tobacco mosaic virus
*20 nm – Length of a nanobe, could be one of the smallest forms of life
*20–80 nm – thickness of cell wall in Gram-positive bacteria
*20 nm – thickness of bacterial flagellum
*22 nm – the average half-pitch of a memory cell manufactured circa 2011–2012
*22 nm – Smallest feature size of production microprocessors in September 2009
*25 nm – diameter of a microtubule
*30 nm – lower size of cooking oil smoke
*32 nm – the average half-pitch of a memory cell manufactured circa 2009–2010
*40 nm – extreme ultraviolet wavelength
*45 nm – the average half-pitch of a memory cell manufactured circa 2007–2008
*50 nm – upper size for airborne virus particles
*50 nm – flying height of the head of a hard disk
*65 nm – the average half-pitch of a memory cell manufactured circa 2005–2006
*58 nm – height of a T7 bacteriophage
*90 nm – Human immunodeficiency virus (HIV) (generally, viruses range in size from 20 nm to 450 nm)
*90 nm – the average half-pitch of a memory cell manufactured circa 2002–2003
*100 nm – Length of a mesoporous silica nanoparticle

100 nanometres

To help compare different orders of magnitude, this section lists lengths between 10⁻⁷ and 10⁻⁶ m (100 nm and 1  μm).

*100 nm – greatest particle size that can fit through a surgical mask
*100 nm – 90% of particles in wood smoke are smaller than this.
*120 nm – greatest particle size that can fit through a ULPA filter
*120 nm – diameter of a human immunodeficiency virus (HIV)
*120 nm – approximate diameter of SARS-CoV-2
*125 nm – standard depth of pits on compact discs (width: 500 nm, length: 850 nm to 3.5 μm)
*180 nm – typical length of the rabies virus
*200 nm – typical size of a ''Mycoplasma'' bacterium, among the smallest bacteria
*300–400 nm – near ultraviolet wavelength
*300 nm – greatest particle size that can fit through a HEPA (high efficiency particulate air) filter (N100 removes up to 99.97% at 0.3 micrometres, N95 removes up to 95% at 0.3 micrometres)
*400–420 nm – wavelength of violet light (see Color and Visible spectrum)
*420–440 nm – wavelength of indigo light
*440–500 nm – wavelength of blue light
*500–520 nm – wavelength of cyan light
*520–565 nm – wavelength of green light
*565–590 nm – wavelength of yellow light
*590–625 nm – wavelength of orange light
*625–700 nm – wavelength of red light
*700–1.4 μm – wavelength of near-infrared radiation

1 micrometre

The ' ( SI symbol: ') is a unit of length in the metric system equal to ().
To help compare different orders of magnitude, this section lists some items with lengths between 10⁻⁶ and 10⁻⁵ m (between 1 and 10 micrometres, or μm).

*~0.7–300 μm – wavelength of infrared radiation
*1 μm – the side of a square of area 10⁻¹² m²
*1 μm – edge of cube of volume 10⁻¹⁸ m³ (1 fL)
*1–10 μm – diameter of a typical bacterium
*1 μm – length of a lysosome
*1–2 μm – anthrax spore
*2 μm – length of an average E. coli bacteria
*3–4 μm – size of a typical yeast cell
*5 μm – length of a typical human spermatozoon's head
*6 μm – thickness of the tape in a 120-minute (C120) compact cassette
*7 μm – diameter of the nucleus of a typical eukaryotic cell
*about 7 μm – diameter of human red blood cells
*3–8 μm – width of strand of spider web silk
*5–10 μm – width of a chloroplast
*8–11 μm – size of a ground-level fog or mist dropletBut not cloud or high-level fog droplets; droplet size increases with altitude. For a contradictory study indicating larger drop sizes even in ground fog, see

10 micrometres

To help compare different orders of magnitude, this section lists lengths between 10⁻⁵ m and 10⁻⁴ m (10 μm and 100 μm).

*10 μm – width of cotton fibre
*10 μm – tolerance of a Lego brick
*10 μm – transistor width of the Intel 4004, the world's first commercial microprocessor
*10 μm – mean longest dimension of a human red blood cell
*5–20 μm – dust mite excreta
*10.6 μm – wavelength of light emitted by a carbon dioxide laser
*15 μm – width of silk fibre
*17 μm – minimum width of a strand of human hair
*17.6 μm – one twip, a unit of length in typography
*10 to 55 μm – width of wool fibre
*25.4 μm – 1/1,000 inch, commonly referred to as 1 mil in the U.S. and 1 thou in the UK
*30 μm – length of a human skin cell
*50 μm – typical length of '' Euglena gracilis'', a flagellate protist
*50 μm – typical length of a human liver cell, an average-sized body cell
*50 μm – length of a silt particle
*60 μm – length of a sperm cell
*70 to 180 μm – thickness of paper

100 micrometres

To help compare different orders of magnitude, this section lists lengths between 10⁻⁴ m and 10⁻³ m (100  μm and 1  mm). The term ''myriometre'' (abbr. mom, equivalent to 100 micrometres; frequently confused with the ''myriametre'', 10 kilometres) is deprecated; the decimal metric prefix myrio- is obsolete and was not included among the prefixes when the International System of Units was introduced in 1960.

*100 μm – 1/10 of a millimetre
*100 μm – 0.00394 inches
*100 μm – smallest distance that can be seen with the naked eye
*100 μm – average diameter of a strand of human hair
*100 μm – thickness of a coat of paint
*100 μm – length of a dust particle
*120 μm – the geometric mean of the Planck length and the diameter of the observable universe:
*120 μm – diameter of a human ovum
*170 μm – length of the largest sperm cell in nature, belonging to the ''Drosophila bifurca'' fruit fly
*181 μm – maximum width of a strand of human hair
*100–400 μm – length of Demodex mites living in human hair follicles
*175–200 μm – typical thickness of a solar cell.
*200 μm – typical length of '' Paramecium caudatum'', a ciliate protist
*200 μm – nominal width of the smallest commonly available mechanical pencil lead (0.2 mm)
*250–300 μm – length of a dust mite
*340 μm – length of a pixel on a 17-inch monitor with a resolution of 1024×768
*500 μm – typical length of ''Amoeba proteus'', an amoeboid protist
*
*500 μm – average length of a grain of sand
*500 μm – average length of a grain of salt
*500 μm – average length of a grain of sugar
*560 μm – thickness of the central area of a human cornea
*750 μm – diameter of a Thiomargarita namibiensis, the largest bacteria known
*760 μm – thickness of an identification card

1 millimetre

The ' ( SI symbol: ') is a unit of length in the metric system equal to ().
To help compare different orders of magnitude, this section lists lengths between 10⁻³ m and 10⁻² m (1 mm and 1 cm).

*1.0 mm – 1/1,000 of a metre
*1.0 mm – 0.03937 inches or 5/127 (exactly)
*1.0 mm – side of a square of area 1 mm²
*1.0 mm – diameter of a pinhead
*1.5 mm – average length of a flea
*2.54 mm – distance between pins on old dual in-line package (DIP) electronic components
*5 mm – length of an average red ant
*5 mm – diameter of an average grain of rice
* 5.56×45mm NATO – standard ammunition size
*6 mm – approximate width of a pencil
*7 mm – length of a ''Paedophryne amauensis'', the smallest-known vertebrate
*7.1 mm – length of a sunflower seed
* 7.62×51mm NATO – common military ammunition size
*8 mm – width of old-format home movie film
*8 mm – length of a ''Paedocypris progenetica'', the smallest-known fish

1 centimetre

The ' ( SI symbol: ') is a unit of length in the metric system equal to ().
To help compare different orders of magnitude, this section lists lengths between 10⁻² m and 10⁻¹ m (1 cm and 1 dm).

*1 cm – 10 millimetres
*1 cm – 0.39 inches
*1 cm – edge of a square of area 1 cm²
*1 cm – edge of a cube of volume 1 mL
*1 cm – length of a coffee bean
*1 cm – approximate width of average fingernail
*1.2 cm – length of a bee
*1.2 cm – diameter of a die
*1.5 cm – length of a very large mosquito
*1.6 cm – length of a Jaragua Sphaero, a very small reptile
*1.7 cm – length of a Thorius arboreus, the smallest salamander
*2 cm – approximate width of an adult human finger
*2.54 cm – 1 inch
*3.08568 cm – 1 attoparsec (10⁻¹⁸ parsecs)
*3.4 cm – length of a quail egg
*3.5 cm – width of film commonly used in motion pictures and still photography
*3.78 cm – amount of distance the Moon moves away from Earth each year
*4.3 cm – minimum diameter of a golf ball
*5 cm – usual diameter of a chicken egg
*5 cm – height of a hummingbird, the smallest-known bird
*5.5 × 5.5 × 5.5 cm – dimensions of a 3x3x3 Rubik's cube
*6.1 cm – average height of an apple
*7.3–7.5 cm – diameter of a baseball
*8.6 cm × 5.4 cm – dimensions of a standard credit card
*9 cm – length of a speckled padloper, the smallest-known turtle

1 decimetre

The ' ( SI symbol: ') is a unit of length in the metric system equal to ().
To help compare different orders of magnitude, this section lists lengths between 10 centimetres and 100 centimetres (10⁻¹ metre and 1 metre).

Conversions

10 centimetres (abbreviated to 10 cm) is equal to:

*1 decimetre (dm), a term not in common use (1 L = 1 dm³.)
*100 millimetres
*3.9 inches
*a side of a square of area 0.01 m²
*the edge of a cube with a volume of m³ (1 L)

Wavelengths

*10 cm = 1.0 dm – wavelength of the highest UHF radio frequency, 3 GHz
*12 cm = 1.2 dm – wavelength of the 2.45 GHz ISM radio band
*21 cm = 2.1 dm – wavelength of the 1.4 GHz hydrogen emission line, a hyperfine transition of the hydrogen atom
*100 cm = 10 dm – wavelength of the lowest UHF radio frequency, 300 MHz

Human-defined scales and structures

*10.16 cm = 1.016 dm – 1 hand used in measuring height of horses (4 inches)
*12 cm = 1.2 dm – diameter of a compact disc (CD) (= 120 mm)
*15 cm = 1.5 dm – length of a Bic pen with cap on
*22 cm = 2.2 dm – diameter of a typical association football (soccer ball)
*30 cm = 3 dm – typical school-use ruler length (= 300 mm)
*30.48 cm = 3.048 dm – 1 foot (measure)
*60 cm = 6 dm – standard depth (front to back) of a domestic kitchen worktop in Europe (= 600 mm)
*90 cm = 9 dm – average length of a rapier, a fencing sword
*91.44 cm = 9.144 dm – one yard (measure)

Nature

*10 cm = 1 dm – diameter of the human cervix upon entering the second stage of labour
*11 cm = 1.1 dm – diameter of an average potato in the US
*13 cm = 1.3 dm – body length of a Goliath birdeater
*15 cm = 1.5 dm – approximate size of largest beetle species
*19 cm = 1.9 dm – length of a banana
*26.3 cm = 2.6 dm – length of average male human foot
*29.98 cm = 2.998 dm – distance light in vacuum travels in one nanosecond
*30 cm = 3.0 dm – maximum leg length of a Goliath birdeater
*31 cm = 3.1 dm – wingspan of largest butterfly species ''Ornithoptera alexandrae''
*46 cm = 4.6 dm – length of an average domestic cat
*50 to 65 cm = 5–6.5 dm – a coati's tail
*66 cm = 6.6 dm – length of the longest pine cones (produced by the sugar pine)

Astronomical

*84 cm = 8.4 dm – approximate diameter of 2008 TS26, a meteoroid

1 metre

To help compare different orders of magnitude, this section lists lengths between one metre and ten metres.
Light, in vacuum, travels 1 metre in , or of a second.

Conversions

1 metre is:
*10 decimetres
*100 centimetres
*1,000 millimetres
*39.37 inches
*3.28 feet
*1.1 yards
*side of square with area 1 m²
*edge of cube with surface area 6 m² and volume 1 m³
*radius of circle with area π m²
*radius of sphere with surface area 4π m² and volume 4/3π m³

Human-defined scales and structures

*1 m – approximate height of the top part of a doorknob on a door
*1 m – diameter of a very large beach ball
*1.435 m – standard gauge of railway track used by about 60% of railways in the world = 4 ft 8 in
*2.5 m – distance from the floor to the ceiling in an average residential house
*2.7 m – length of the Starr Bumble Bee II, the smallest plane
*2.77–3.44 m – wavelength of the broadcast radio FM band 87–108 MHz
*3.05 m – the length of an old Mini
*8.38 m – the length of a London Bus (AEC Routemaster)

Sports

*2.44 m – height of an association football goal
*2.45 m – highest high jump by a human (Javier Sotomayor)
*3.05 m – (10 feet) height of the basket in basketball
*8.95 m – longest long jump by a human (Mike Powell)

Nature

*1 m – height of ''Homo floresiensis'' (the "Hobbit")

*1.15 m – a pizote (mammal)
*1.63 m – (5 feet 4 inches) (or 64 inches) – height of average U.S. female human (source: U.S. Centers for Disease Control and Prevention (CDC))
*1.75 m – (5 feet 8 inches) – height of average U.S. male human (source: U.S. CDC as per female above)
*2.5 m – height of a sunflower
*2.72 m – (8 feet 11 inches) – tallest-known human (Robert Wadlow)
*3.63 m – the record wingspan]for living birds (a wandering albatross)
*5 m – length of an elephant
*5.2 m – height of a giraffe
*5.5 m – height of a ''Baluchitherium'', the largest land mammal ever lived
*6.5 m – wingspan of ''Argentavis'', the largest flying bird known
*7.4 m – wingspan of ''Pelagornis,'' the bird with longest wingspan ever.
*7.5 m – approximate length of the human gastrointestinal tract

Astronomical

*3–6 m – approximate diameter of , a meteoroid
*4.1 m – diameter of 2008 TC3, a small asteroid that flew into the Earth's atmosphere on October 7, 2008

1 decametre

The ' ( SI symbol: ') is a unit of length in the metric system equal to 10 metres (10¹ m).
To help compare different orders of magnitude, this section lists lengths between 10 and 100 metres.

Conversions

10 metres (very rarely termed a decametre which is abbreviated as dam) is equal to:
*10 metres
*100 decimetres
*1,000 centimetres
*10,000 millimetres
*32.8 feet
*11 yards
*side of a square with area 100 m²

Human-defined scales and structures

*10 metres – wavelength of the highest shortwave radio frequency, 30 M Hz
*23 metres – height of the obelisk of the Place de la Concorde, Paris, France
*25 metres – wavelength of the broadcast radio shortwave band at 12 MHz
*29 metres – height of the lighthouse at Savudrija, Croatia
*31 metres – wavelength of the broadcast radio shortwave band at 9.7 MHz
*34 metres – height of the Split Point Lighthouse in Aireys Inlet, Victoria, Australia
*40 metres – average depth beneath the seabed of the Channel tunnel
*49 metres – wavelength of the broadcast radio shortwave band at 6.1 MHz
*50 metres – length of a road train
*55 metres – height of the Leaning Tower of Pisa
*62.5 metres – height of Pyramid of Djoser
*64 metres – wingspan of a Boeing 747-400
*69 metres – wingspan of an Antonov An-124 Ruslan
*70 metres – length of the Bayeux Tapestry
*70 metres – width of a typical association football field
*77 metres – wingspan of a Boeing 747-8
*88.4 metres – wingspan of an Antonov An-225 ''Mriya'' transport aircraft
*93 metres – height of the Statue of Liberty
*96 metres – height of Big Ben
*100 metres – wavelength of the lowest shortwave radio frequency, 3 MHz

Sports

*11 metres – approximate width of a doubles tennis court
*15 metres – width of a standard FIBA basketball court
*15.24 metres – width of an NBA]basketball court (50 feet)
*18.44 metres – distance between the front of the pitcher's rubber and the rear point of home plate on a baseball field (60 feet, 6 inches)
*20 metres – length of cricket pitch (22 yards)
*27.43 metres – distance between bases on a baseball field (90 feet)
*28 metres – length of a standard FIBA basketball court
*28.65 metres – length of an NBA basketball court (94 feet)
*49 metres – width of an American football field (53 yards)
*59.436 metres – width of a Canadian football field (65 yards)
*70 metres – typical width of a soccer field
*91 metres – length of an American football field (100 yards, measured between the goal lines)

Nature

*10 metres – average length of human digestive tract
*12 metres – length of a whale shark, largest living fish
*12 metres – wingspan of a ''Quetzalcoatlus'', a pterosaur
*13 metres – length of a giant squid and colossal squid, the largest living invertebrates
*15 metres – approximate distance the tropical circles of latitude are moving towards the equator and the polar circles are moving towards the poles each year due to a natural, gradual decrease in the Earth's axial tilt
*18 metres – height of a ''Sauroposeidon'', the tallest-known dinosaur
*20 metres – length of a ''Leedsichthys'', the largest-known fish to have lived
*21 metres – height of High Force waterfall in England
*33 metres – length of a blue whale, the largest animal on earth, living or extinct, in terms of mass
*39 metres – length of a ''Supersaurus'', the longest-known dinosaur and longest vertebrate
*52 metres – height of Niagara Falls
*55 metres – length of a bootlace worm, the longest-known animal
*83 metres – height of a Western hemlock

Astronomical

*30 metres – diameter of , a rapidly spinning meteoroid
*30.8568 metres – 1 femtoparsec
*32 metres – approximate diameter of 2008 HJ, a small meteoroid

1 hectometre

The ' ( SI symbol: ') is a unit of length in the metric system equal to 100 metres (10² m).
To compare different orders of magnitude this section lists lengths between 100 metres and 1,000 metres (1 kilometre).

Conversions

100 metres (sometimes termed a hectometre) is equal to:

*328 feet
*one side of a 1 hectare square
*a fifth of a modern li, a Chinese unit of measurement
*the approximate distance travelled by light in 300 nanoseconds

Human-defined scales and structures

*100 metres – wavelength of the highest medium wave radio frequency, 3 MHz
*100 metres – spacing of location marker posts on British motorways
*138.8 metres – height of the Great Pyramid of Giza (Pyramid of Cheops)
*139 metres – height of the world's tallest roller coaster, Kingda Ka
*187 metres – shortest wavelength of the broadcast radio AM band, 1600 kHz
*202 metres – length of the Széchenyi Chain Bridge connecting Buda and Pest
*318 metres – height of The New York Times Building
*318.9 metres – height of the Chrysler Building
*328 metres – height of Auckland's Sky Tower, the tallest free-standing structure in the Southern Hemisphere
*330 metres – height of the Eiffel Tower (including antenna)
*341 metres – height of the world's tallest bridge, the Millau Viaduct
*390 metres – height of the Empire State Building
*400–800 metres – heights of the world's tallest skyscrapers of the past 80 years
*458 metres – length of the Knock Nevis, the world's largest supertanker
*553.33 metres – height of the CN Tower
*555 metres – longest wavelength of the broadcast radio AM band, 540 kHz
*630 metres – height of the KVLY-TV mast, second-tallest structure in the world
*646 metres – height of the Warsaw radio mast, the world's tallest structure until its collapse in 1991
*828 metres – height of Burj Khalifa, world's tallest structure on 17 January 2009
*1,000 metres – wavelength of the lowest mediumwave radio frequency, 300 kHz

Sports

*100 metres – the distance a very fast human can run in about 10 seconds
*100.584 metres – length of a Canadian football field between the goal lines (110 yards)
*91.5 metres – 137 metres – length of a soccer field
*105 metres – length of football pitch (UEFA stadium categories 3 and 4)
*105 metres – length of a typical football field
*109.73 metres – total length of an American football field (120 yards, including the end zones)
*110–150 metres – the width of an Australian football field
*135–185 metres – the length of an Australian football field
*137.16 metres – total length of a Canadian football field, including the end zones (150 yards)

Nature

*115.5 metres – height of the world's tallest tree in 2007, the Hyperion sequoia
*310 metres – maximum depth of Lake Geneva
*340 metres – distance sound travels in air at sea level in one second; see Speed of sound
*979 metres – height of the Salto Angel, the world's highest free-falling waterfall (Venezuela)
*1500 metres – distance sound travels in water in one second

Astronomical

*270 metres – length of 99942 Apophis
*535 metres – length of 25143 Itokawa, a small asteroid visited by a spacecraft

1 kilometre

The ' ( SI symbol: ') is a unit of length in the metric system equal to  metres (10³ m).
To help compare different orders of magnitude, this section lists lengths between 1 kilometre and 10 kilometres (10³ and 10⁴ metres).

Conversions

1 kilometre (unit symbol km) is equal to:

*1,000 metres
*0.621371 miles
*1,093.61 yards
*3,280.84 feet
*39,370.1 inches
*100,000 centimetres
*1,000,000 millimetres
*Side of a square of area 1 km²
*Radius of a circle of area π km²

Human-defined scales and structures

*1 km – wavelength of the highest long wave radio frequency, 300 kHz
*1.280 km – span of the Golden Gate Bridge (distance between towers)
*1.609 km – 1 statute mile
*1.852 km – 1 nautical mile, equal to 1 arcminute of latitude at the surface of the Earth
*1.991 km – span of the Akashi Kaikyō Bridge
*2.309 km – axial length of the Three Gorges Dam, the largest dam in the world
*3.991 km – length of the Akashi Kaikyō Bridge, longest suspension bridge in the world
*5.072 km – height of Tanggula Mountain Pass, below highest peak in the Tanggula Mountains, highest railway pass in the world
*5.727 km – height of Cerro Aucanquilcha, highest road in the world, located in Chile
* 98 airports have paved runways from 4 km to 5.5 km in length.
*8 km – length of Palm Jebel Ali, an artificial island built off the coast of Dubai
*9.8 km – length of The World, an artificial archipelago that is also built off the coast of Dubai, whose islands resemble a world map

Geographical

*1.637 km – deepest dive of Lake Baikal in Russia, the world's largest freshwater lake
*2.228 km – height of Mount Kosciuszko, highest point on mainland Australia
*Most of Manhattan is from 3 to 4 km wide.
*4.810 km – height of Mont Blanc, highest peak in the Alps
*4.884 km – height of Carstensz Pyramid, highest peak in Oceania
*4.892 km – height of Mount Vinson, highest peak in Antarctica
*5.610 km – height of Mount Damavand, highest peak in Iran
*5.642 km – height of Mount Elbrus, highest peak in Europe
*5.895 km – height of Mount Kilimanjaro, highest peak in Africa
*6.081 km – height of Mount Logan, highest peak in Canada
*6.190 km – height of Denali, highest peak in North America
*6.959 km – height of Aconcagua, highest peak in South America
*7.5 km – depth of Cayman Trench, deepest point in the Caribbean Sea
*8.848 km – height of Mount Everest, highest peak on Earth, on the border between Nepal and China

Astronomical

*1 km – diameter of 1620 Geographos
*1 km – very approximate size of the smallest-known moons of Jupiter
*1.4 km – diameter of Dactyl, the first confirmed asteroid moon
*4.8 km – diameter of 5535 Annefrank, an inner belt asteroid
*5 km – diameter of 3753 Cruithne
*5 km – length of PSR B1257+12
*8 km – diameter of Themisto, one of Jupiter's moons
*8 km – diameter of the Vela Pulsar
*8.6 km – diameter of Callirrhoe, also known as Jupiter XVII
*9.737 km – length of PSR B1919+21

10 kilometres

To help compare different orders of magnitude, this section lists lengths between 10 and 100 kilometres (10⁴ to 10⁵ metres). The ''myriametre'' (Website based on ''Alte Meß- und Währungssysteme aus dem deutschen Sprachgebiet'', ) (sometimes also spelled ''myriometre''; 10,000 metres) is a deprecated unit name; the decimal metric prefix myria- (sometimes also written as myrio-) is obsolete and not included among the prefixes when the International System of Units was introduced in 1960.

Conversions

10 kilometres is equal to:

*10,000 metres
*6.2 miles
*1 ''mil (the Scandinavian mile)'', now standardized as 10 km:
**1 mil, the unit of measure commonly used in Norway and SwedenHaugen, Einar, ''Norwegian English Dictionary,'' 1965, Oslo: Universitetsforlaget and Madison: University of Wisconsin Press, s.v. mil used to be 11,295 m in Norway and 10,688 m in Sweden.
*'' farsang'', unit of measure commonly used in Iran and Turkey

Sports

*42.195 km – length of the marathon

Human-defined scales and structures

*18 km – cruising altitude of Concorde
*27 km – circumference of the Large Hadron Collider, the largest and highest energy particle accelerator
*34.668 km – highest manned balloon flight (Malcolm D. Ross and Victor E. Prather on 4 May 1961)
*38.422 km – length of the Second Lake Pontchartrain Causeway in Louisiana, US
*39 km – undersea portion of the Channel tunnel
*53.9 km – length of the Seikan Tunnel, , the longest rail tunnel in the world
*77 km – rough total length of the Panama Canal

Geographical

*10 km – height of Mauna Kea in Hawaii, measured from its base on the ocean floor
*11 km – deepest-known point of the ocean, Challenger Deep in the Mariana Trench
*11 km – average height of the troposphere
*14 km – width of the Gibraltar strait
*21 km – length of Manhattan
*23 km – depth of the largest earthquake ever recorded in the United Kingdom, in 1931 at the Dogger Bank of the North Sea
*34 km – narrowest width of the English Channel at the Strait of Dover
*50 km – approximate height of the stratosphere
*90 km – width of the Bering Strait

Astronomical

*10 km – diameter of the most massive neutron stars (3–5 solar masses)
*13 km – mean diameter of Deimos, the smaller moon of Mars
*20 km – diameter of the least massive neutron stars (1.44 solar masses)
*20 km – diameter of Leda, one of Jupiter's moons
*20 km – diameter of Pan, one of Saturn's moons
*22 km – diameter of Phobos, the larger moon of Mars
*27 km – height of Olympus Mons above the Mars reference level, the highest-known mountain of the Solar System
*30.8568 km – 1 picoparsec
*43 km – diameter difference of Earth's equatorial bulge
*66 km – diameter of Naiad, the innermost of Neptune's moons

100 kilometres

A length of ''100 kilometres'' (about 62 miles), as a rough amount, is relatively common in measurements on Earth and for some astronomical objects.
It is the altitude at which the FAI defines spaceflight to begin.

To help compare orders of magnitude, this section lists lengths between 100 and 1,000 kilometres (10⁵ and 10⁶ metres).

Conversions

A distance of 100 kilometres is equal to about 62 miles (or ).

Human-defined scales and structures

*100 km – the Karman line: the official boundary of outer space
*105 km – distance from Giridih to Bokaro
*109 km – length of High Speed 1 between London and the Channel Tunnel
*130 km – range of a Scud-A missile
*163 km – length of the Suez Canal
*164 km – length of the Danyang–Kunshan Grand Bridge
*213 km – length of Paris Métro
*217 km – length of the Grand Union Canal
*223 km – length of the Madrid Metro
*300 km – range of a Scud-B missile
*386 km – altitude of the International Space Station
*408 km – length of the London Underground (active track)
*460 km – distance from London to Paris
*470 km – distance from Dublin to London as the crow flies
*600 km – range of a Scud-C missile
*600 km – height above ground of the Hubble Space Telescope
*804.67 km – (500 miles) distance of the Indy 500 automobile race

Geographical

*111 km – distance covered by one degree of latitude on Earth's surface
*180 km – distance between Mumbai and Nashik
*203 km – length of Sognefjorden, the third-largest fjord in the world
*220 km – distance between Pune and Nashik
*240 km – widest width of the English Channel
*430 km – length of the Pyrenees
*500 km – widest width of Sweden from east to west
*550 km – distance from San Francisco to Los Angeles as the crow flies
*560 km – distance of Bordeaux–Paris, formerly the longest one-day professional cycling race
*590 km – length of land boundary between Finland and Sweden
*724 km – length of the Om River
*871 km – distance from Sydney to Melbourne (along the Hume Highway)
*897 km – length of the River Douro
*900 km – distance from Berlin to Stockholm
*956 km – distance from Washington, D.C. to Chicago, Illinois as the crow flies

Astronomical

*100 km – the altitude at which the FAI defines spaceflight to begin
*167 km – diameter of Amalthea, one of Jupiter's inner moons
*200 km – width of Valles Marineris
*220 km – diameter of Phoebe, the largest of Saturn's outer moons
*300 km – the approximate distance travelled by light in one millisecond
*340 km – diameter of Nereid, the third-largest moon of Neptune
*350 km – lower bound of Low Earth orbit
*420 km – diameter of Proteus, the second-largest moon of Neptune
*468 km – diameter of the asteroid 4 Vesta
*472 km – diameter of Miranda, one of Uranus's major moons
*974.6 km – greatest diameter of 1 Ceres, the largest Solar System asteroid

1 megametre

The ' ( SI symbol: ') is a unit of length in the metric system equal to  metres (10⁶ m).
To help compare different orders of magnitude, this section lists lengths starting at 10⁶ m ( 1 Mm or 1,000 km).

Conversions

1 megametre is equal to:
*1 E+6 m (one million metres)
*approximately 621.37 miles
*Side of square with area 1,000,000 km²

Human-defined scales and structures

*2.100 Mm – Length of proposed gas pipeline from Iran to India via Pakistan
*2.100 Mm – Distance from Casablanca to Rome
*2.288 Mm – Length of the official Alaska Highway