
Decimal time is the representation of the time of day using units which are
decimal
The decimal numeral system (also called the base-ten positional numeral system and denary or decanary) is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers (''decimal fractions'') of th ...
ly related. This term is often used specifically to refer to the
French Republican calendar time system used in
France
France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...
from 1794 to 1800, during the
French Revolution, which divided the day into 10 decimal hours, each decimal hour into 100 decimal minutes and each decimal minute into 100 decimal seconds (100,000 decimal seconds per day), as opposed to the more familiar
standard time
Standard time is the synchronization of clocks within a geographical region to a single time standard, rather than a local mean time standard. Generally, standard time agrees with the local mean time at some meridian that passes through the r ...
, which divides the day into 24
hour
An hour (symbol: h; also abbreviated hr) is a unit of time historically reckoned as of a day and defined contemporarily as exactly 3,600 seconds ( SI). There are 60 minutes in an hour, and 24 hours in a day.
The hour was initially establis ...
s, each hour into 60
minutes and each minute into 60
second
The second (symbol: s) is a unit of time derived from the division of the day first into 24 hours, then to 60 minutes, and finally to 60 seconds each (24 × 60 × 60 = 86400). The current and formal definition in the International System of U ...
s (86,400
SI seconds per day).
The main advantage of a decimal time system is that, since the
base used to divide the time is the same as the one used to represent it, the representation of hours, minutes and seconds can be handled as a unified value. Therefore, it becomes simpler to interpret a timestamp and to perform conversions. For instance, 12345 is 1 decimal hour, 23 decimal minutes, and 45 decimal seconds, or 1.2345 decimal hours, or 123.45 decimal minutes or 12345 decimal seconds; 3 hours is 300 minutes or 30,000 seconds.
This property also makes it straightforward to represent a timestamp as a
fractional day, so that .54321 can be interpreted as five decimal hours, 43 decimal minutes and 21 decimal seconds after the start of that day, or a fraction of 0.54321 (54.321%) through that day (which is shortly after traditional 13:00). It also adjusts well to digital time representation using
epochs, in that the internal time representation can be used directly both for computation and for user-facing display.
History
Egypt
The decans are 36 groups of stars (small constellations) used in the ancient Egyptian astronomy to conveniently divide the 360 degree ecliptic into 36 parts of 10 degrees. Because a new decan also appears heliacally every ten days (that is, every ten days, a new decanic star group reappears in the eastern sky at dawn right before the Sun rises, after a period of being obscured by the Sun's light), the ancient Greeks called them ''dekanoi'' (δεκανοί; pl. of δεκανός ''dekanos'') or "tens". A ten-day period between the rising of two consecutive decans is a decade. There were 36 decades (36 × 10 = 360 days), plus five added days to compose the 365 days of a solar based year.
China
Decimal time was used in China throughout most of its history alongside
duodecimal
The duodecimal system, also known as base twelve or dozenal, is a positional numeral system using twelve as its base. In duodecimal, the number twelve is denoted "10", meaning 1 twelve and 0 units; in the decimal system, this number is i ...
time. The midnight-to-midnight day was divided both into 12 double hours () and also into 10 shi / 100 ''ke'' () by the 1st millennium BC. Other numbers of ''ke'' per day were used during three short periods: 120 ''ke'' from 5 to 3 BC, 96 ''ke'' from 507 to 544 CE, and 108 ''ke'' from 544 to 565. Several of the roughly 50 Chinese calendars also divided each ''ke'' into 100 ''fen'', although others divided each ''ke'' into 60 ''fen''. In 1280, the ''Shoushi'' (Season Granting) calendar further subdivided each ''fen'' into 100 ''miao'', creating a complete decimal time system of 100 ''ke'', 100 ''fen'' and 100 ''miao''. Chinese decimal time ceased to be used in 1645 when the
Shíxiàn calendar, based on European astronomy and brought to China by the
Jesuit
The Society of Jesus (; abbreviation: S.J. or SJ), also known as the Jesuit Order or the Jesuits ( ; ), is a religious order (Catholic), religious order of clerics regular of pontifical right for men in the Catholic Church headquartered in Rom ...
s, adopted 96 ''ke'' per day alongside 12 double hours, making each ''ke'' exactly one-quarter hour.
Gēng (更) is a time signal given by drum or gong. The character for gēng 更, literally meaning "rotation" or "watch", comes from the rotation of watchmen sounding these signals. The first gēng theoretically comes at sundown, but was standardized to fall at 19:12. The time between each gēng is 1⁄10 of a day, making a gēng 2.4 hours long (2 hours 24 minutes). As a 10-part system, the gēng are strongly associated with the 10 celestial stems, especially since the stems are used to count off the gēng during the night in Chinese literature.
As early as the Bronze-Age Xia dynasty, days were grouped into ten-day weeks known as xún (旬). Months consisted of three xún. The first 10 days were the early xún (上旬), the middle 10 the mid xún (中旬), and the last nine or 10 days were the late xún (下旬). Japan adopted this pattern, with 10-day-weeks known as jun (旬). In Korea, they were known as sun (순,旬).
France
Pre-Revolution
In 1754,
Jean le Rond d'Alembert wrote in the ''
Encyclopédie
, better known as ''Encyclopédie'' (), was a general encyclopedia published in France between 1751 and 1772, with later supplements, revised editions, and translations. It had many writers, known as the Encyclopédistes. It was edited by Denis ...
'':
:It would be very desirable that all divisions, for example of the ''livre'', the ''sou'', the ''toise'', the day, the hour, etc. would be from tens into tens. This division would result in much easier and more convenient calculations and would be very preferable to the arbitrary division of the ''livre'' into twenty ''sous'', of the ''sou'' into twelve ''deniers'', of the day into twenty-four hours, the hour into sixty minutes, etc.
In 1788,
Claude Boniface Collignon proposed dividing the day into 10 hours or 1,000 minutes, each new hour into 100 minutes, each new minute into 1,000 seconds, and each new second into 1,000 ''
tierces'' (older French for "third"). The distance the
twilight zone travels in one such ''tierce'' at the
equator
The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...
, which would be one-billionth of the
circumference
In geometry, the circumference () is the perimeter of a circle or ellipse. The circumference is the arc length of the circle, as if it were opened up and straightened out to a line segment. More generally, the perimeter is the curve length arou ...
of the
earth
Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
, would be a new unit of length, provisionally called a half-
handbreadth, equal to four modern
centimetre
upright=1.35, Different lengths as in respect to the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is in-between 1 meter to 1 millimeter.
A centimetre (International spelling) or centimeter (American ...
s. Further, the new ''tierce'' would be divided into 1,000 ''quatierces'', which he called "microscopic points of time". He also suggested a week of 10 days and dividing the year into 10 "solar months".
French Republic
Decimal time was officially introduced during the
French Revolution.
Jean-Charles de Borda made a proposal for decimal time on 5 November 1792. The
National Convention
The National Convention () was the constituent assembly of the Kingdom of France for one day and the French First Republic for its first three years during the French Revolution, following the two-year National Constituent Assembly and the ...
issued a decree on 5 October 1793, to which the underlined words were added on 24 November 1793 (4
Frimaire
Frimaire () was the third month in the French Republican calendar. The month was named after the French word ''frimas'' 'frost'.
Frimaire was the third month of the autumn quarter (''mois d'automne''). It started between 21 November and 23 Novem ...
of the Year II):
:VIII. Each month is divided into three equal parts, of ten days each, which are called ''décades''...
:XI. The day, from midnight to midnight, is divided into ten parts
or hours, each part into ten others, so on until the smallest measurable portion of the duration.
The hundredth part of the hour is called ''decimal minute''; the hundredth part of the minute is called ''decimal second''. This article will not be required for the public records, until from the
1st of Vendémiaire, the year three of the Republic. (September 22, 1794) (emphasis in original)
Thus, midnight was called ''dix heures'' ("ten hours"'')'', noon was called ''cinq heures'' ("five hours"), etc.
Representation

The colon (:) was not yet in use as a unit separator for standard times, and is used for non-decimal bases. The French
decimal separator
FIle:Decimal separators.svg, alt=Four types of separating decimals: a) 1,234.56. b) 1.234,56. c) 1'234,56. d) ١٬٢٣٤٫٥٦., Both a comma and a full stop (or period) are generally accepted decimal separators for international use. The apost ...
is the comma (,), while the period (.), or "point", is used in English. Units were either written out in full, or abbreviated. Thus, five hours eighty three minutes decimal might be written as 5 h. 83 m. Even today, "h" is commonly used in France to separate hours and minutes of 24-hour time, instead of a colon, such as 14h00. Midnight was represented in civil records as "ten hours". Times between midnight and the first decimal hour were written without hours, so 1:00 am, or 0.41 decimal hours, was written as "four décimes" or "forty-one minutes". 2:00 am (0.8333) was written as "eight décimes", "eighty-three minutes", or even "eighty-three minutes thirty-three seconds".
As with duodecimal time, decimal time was represented according to true solar time, rather than mean time, with noon being marked when the sun reached its highest point locally, which varied at different locations, and throughout the year.
In "Methods to find the Leap Years of the French Calendar", Jean-Baptiste-Joseph Delambre used three different representations for the same decimal time:
* 0,386 (comma is the decimal sign in French)
* 0
j386 ("j" is for jour, day in French)
* 3
h 86' (apostrophe is for minutes)

Sometimes in official records, decimal hours were divided into tenths, or ''décimes'', instead of minutes. One ''décime'' is equal to 10 decimal minutes, which is nearly equal to a quarter-hour (15 minutes) in standard time. Thus, "five hours two décimes" equals 5.2 decimal hours, roughly 12:30 p.m. in standard time. One hundredth of a decimal second was a decimal ''tierce''.
Usage
Although
clock
A clock or chronometer is a device that measures and displays time. The clock is one of the oldest Invention, human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, a ...
s and
watch
A watch is a timepiece carried or worn by a person. It is designed to maintain a consistent movement despite the motions caused by the person's activities. A wristwatch is worn around the wrist, attached by a watch strap or another type of ...
es were produced with faces showing both standard time with numbers 1–24 and decimal time with numbers 1–10, decimal time never caught on; it was not used for public records until the beginning of the Republican year III, 22 September 1794, and mandatory use was suspended 7 April 1795 (18
Germinal of the Year III). In spite of this, decimal time was used in many cities, including
Marseille
Marseille (; ; see #Name, below) is a city in southern France, the Prefectures in France, prefecture of the Departments of France, department of Bouches-du-Rhône and of the Provence-Alpes-Côte d'Azur Regions of France, region. Situated in the ...
and
Toulouse
Toulouse (, ; ; ) is a city in southern France, the Prefectures in France, prefecture of the Haute-Garonne department and of the Occitania (administrative region), Occitania region. The city is on the banks of the Garonne, River Garonne, from ...
, where a decimal clock with just an hour hand was on the front of the
Capitole for five years.
In some places, decimal time was used to record certificates of births, marriages, and deaths until the end of Year VIII (September 1800). On the
Palace of the Tuileries in
Paris
Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...
, two of the four clock faces displayed decimal time until at least 1801. The mathematician and astronomer
Pierre-Simon Laplace
Pierre-Simon, Marquis de Laplace (; ; 23 March 1749 – 5 March 1827) was a French polymath, a scholar whose work has been instrumental in the fields of physics, astronomy, mathematics, engineering, statistics, and philosophy. He summariz ...
had a decimal watch made for him, and used decimal time in his work, in the form of
fractional days.
Decimal time was part of a larger attempt at
decimalisation
Decimalisation or decimalization (see American and British English spelling differences, spelling differences) is the conversion of a system of currency or of weights and measures to units related by Power of 10, powers of 10.
Most countries have ...
in revolutionary France (which also included decimalisation of currency and
metrication
Metrication or metrification is the act or process of converting to the metric system of measurement. All over the world, countries have transitioned from local and traditional Unit of measurement, units of measurement to the metric system. This ...
) and was introduced as part of the
French Republican Calendar, which, in addition to decimally dividing the day, divided the month into three ''décades'' of 10 days each; this calendar was abolished at the end of 1805. The start of each year was determined according to the day of the
autumnal equinox, in relation to true or
apparent solar time at the
Paris Observatory.
Metric system
In designing the new metric system, the intent was to replace all the various units of different bases with a small number of standard decimal units. This was to include units for length, weight, area, liquid capacity, volume, and money. Initially the traditional second of time equal to 1/86400 day was proposed as the base of the metric system, but this was changed in 1791 to base the meter on a decimal division of a measurement of the Earth, instead. Early drafts of the metric system published in 1793 included the new decimal divisions of the day included with the Republican calendar, and some of the same individuals were involved with both projects.
On March 28, 1794,
Joseph-Louis Lagrange
Joseph-Louis Lagrange (born Giuseppe Luigi Lagrangia[Carl Friedrich Gauss
Johann Carl Friedrich Gauss (; ; ; 30 April 177723 February 1855) was a German mathematician, astronomer, geodesist, and physicist, who contributed to many fields in mathematics and science. He was director of the Göttingen Observatory and ...](_blank)
recommended the ephemeris second as a metric base unit for time interval in 1832, which eventually became the atomic second in the
International System. However, for longer periods of time interval, the old non-decimal units were approved for use.
Later proposals
At the
International Meridian Conference
The International Meridian Conference was a conference held in October 1884 in Washington, D.C., in the United States, to determine a prime meridian for international use. The conference was held at the request of President of the United State ...
of 1884, the following resolution was proposed by the French delegation and passed
nem con (with 3 abstentions):
:VII. That the Conference expresses the hope that the technical studies designed to regulate and extend the application of the decimal system to the division of angular space and of time shall be resumed, so as to permit the extension of this application to all cases in which it presents real advantages.
In the 1890s, Joseph Charles François de Rey-Pailhade, president of the Toulouse Geographical Society, proposed dividing the day into 100 parts, called ''cés'', equal to 14.4 standard minutes, and each divided into 10 ''decicés'', 100 ''centicés'', etc. The Toulouse Chamber of Commerce adopted a resolution supporting his proposal in April 1897. Although widely published, the proposal received little backing.
The French made another attempt at the decimalization of time in 1897, when the ''Commission de décimalisation du temps'' was created by the
Bureau des Longitudes, with the mathematician
Henri Poincaré
Jules Henri Poincaré (, ; ; 29 April 185417 July 1912) was a French mathematician, Theoretical physics, theoretical physicist, engineer, and philosophy of science, philosopher of science. He is often described as a polymath, and in mathemati ...
as secretary. The commission adopted a compromise, originally proposed by Henri de Sarrauton of the Oran Geographical Society, of retaining the 24-hour day, but dividing each hour into 100 decimal minutes, and each minute into 100 seconds. The plan did not gain acceptance and was abandoned in 1900.
Switzerland

On 23 October 1998, the
Swiss watch company
Swatch introduced a decimal time called
Internet Time for its line of digital watches, which divided the day into 1,000 "''.beats''", (each 86.4 seconds in standard time) counted from 000–999, with @000 being midnight and @500 being noon
standard time
Standard time is the synchronization of clocks within a geographical region to a single time standard, rather than a local mean time standard. Generally, standard time agrees with the local mean time at some meridian that passes through the r ...
in
Switzerland
Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...
, which is
Central European Time
Central European Time (CET) is a standard time of Central, and parts of Western Europe, which is one hour ahead of Coordinated Universal Time (UTC).
The UTC offset, time offset from UTC can be written as UTC+01:00.
It is used in most parts of Eur ...
(one hour ahead of
Universal Time).
Although Swatch did not specify units smaller than one .beat, third party implementations extended the standard by adding "centibeats" or "sub-beats", for extended precision: @248.00. Each "centibeat" was a hundredth of a .beat and was therefore equal to one French decimal second (0.864 seconds).
When using .beats and centibeats, Swatch Internet Time divided the day into 1,000 French decimal minutes and each decimal minute into 100 decimal seconds. So 9pm was 21:00:00 in standard time and @875.00 in extended Swatch Internet Time.
Swatch no longer markets digital watches with Internet Time.
Conversions
There are exactly 86,400 standard seconds (see
SI for the current definition of the standard second) in a standard day, but in the French decimal time system there were 100,000 decimal seconds in the day; thus, the decimal second was 13.6% shorter than its standard counterpart.
Decimal hours
Another common type of decimal time is decimal hours. In 1896, Henri de Sarrauton of the Oran Geographical Society proposed dividing the 24 hours of the day each into 100 decimal minutes, and each minute into 100 decimal seconds. Although endorsed by the Bureau des Longitudes, this proposal failed, but using decimal fractions of an hour to represent the time of day instead of minutes has become common.
Decimal hours are frequently used in accounting for payrolls and hourly billing.
Time clocks typically record the time of day in tenths or hundredths of an hour. For instance, 08:30 would be recorded as 08.50. This is intended to make accounting easier by eliminating the need to convert between minutes and hours.
For aviation purposes, where it is common to add times in an already complicated environment, time tracking is simplified by recording decimal fractions of hours. For instance, instead of adding 1:36 to 2:36, getting 3:72 and converting it to 4:12, one would add 1.6 to 2.6 and get 4.2 hours.
Fractional days
The time of day is sometimes represented as a decimal fraction of a day in science and computers. Standard 24-hour time is converted into a fractional day by dividing the number of hours elapsed since midnight by 24 to make a
decimal fraction
The decimal numeral system (also called the base-ten positional numeral system and denary or decanary) is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers (''decimal fractions'') of the ...
. Thus, midnight is 0.0 day, noon is 0.5 d, etc., which can be added to any type of date, including the following, all of which refer to the same moment in time:
*
Gregorian dates: 2000 January 1.5
*
Two-line elements: 00001.50000000
*
Julian dates: 2451545.0
*
Excel serial dates: 36526.5
As many decimal places may be used as required for precision, so 0.5 d = 0.500000 d. Fractional days are often calculated in
UTC or
TT, although Julian Dates use pre-1925 astronomical date/time (each date began at noon = ".0") and
Microsoft Excel
Microsoft Excel is a spreadsheet editor developed by Microsoft for Microsoft Windows, Windows, macOS, Android (operating system), Android, iOS and iPadOS. It features calculation or computation capabilities, graphing tools, pivot tables, and a ...
uses the local time zone of the computer. Using fractional days reduces the number of units in time calculations from four (days, hours, minutes, seconds) to just one (days).
Fractional days are often used by
astronomer
An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...
s to record observations, and were expressed in relation to Paris Mean Time by the 18th century French mathematician and astronomer
Pierre-Simon Laplace
Pierre-Simon, Marquis de Laplace (; ; 23 March 1749 – 5 March 1827) was a French polymath, a scholar whose work has been instrumental in the fields of physics, astronomy, mathematics, engineering, statistics, and philosophy. He summariz ...
, as in these examples:
Fractional days have been used by astronomers ever since. For instance, the 19th century British astronomer
John Herschel
Sir John Frederick William Herschel, 1st Baronet (; 7 March 1792 – 11 May 1871) was an English polymath active as a mathematician, astronomer, chemist, inventor and experimental photographer who invented the blueprint and did botanical work. ...
gave these examples:
Fractional days are commonly used to express
epoch
In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured.
The moment of epoch is usually decided b ...
s of
orbital elements
Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same o ...
. The decimal fraction is usually added to the calendar date or
Julian day
The Julian day is a continuous count of days from the beginning of the Julian period; it is used primarily by astronomers, and in software for easily calculating elapsed days between two events (e.g., food production date and sell by date).
Th ...
for natural objects, or to the
ordinal date for artificial satellites in
two-line elements.
Decimal multiples and fractions of the second
The second is the
International System of Units (SI) unit of time duration. It is also the standard single-unit time representation in many programming languages, most notably C, and part of UNIX/POSIX standards used by Linux, Mac OS X, etc.; to convert fractional days to fractional seconds, multiply the number by 86400. Fractional seconds are represented as
milliseconds (ms),
microsecond
A microsecond is a unit of time in the International System of Units (SI) equal to one millionth (0.000001 or 10−6 or ) of a second. Its symbol is μs, sometimes simplified to us when Unicode is not available.
A microsecond is to one second, ...
s (μs) or
nanoseconds (ns). Absolute times are usually represented relative to 1 January 1970, at midnight UT. Other systems may use a different zero point (like
Unix time
Unix time is a date and time representation widely used in computing. It measures time by the number of non-leap seconds that have elapsed since 00:00:00 Coordinated Universal Time, UTC on 1 January 1970, the Unix Epoch (computing), epoc ...
).
In principle, time spans greater than one second may be given in units such as
kiloseconds (ks),
megaseconds (Ms),
gigaseconds (Gs),
and so on. Occasionally, these units can be found in technical literature, but traditional units like minutes, hours, days and years are much more common, and are accepted for use with SI.
It is possible to specify the time of day as the number of kiloseconds of elapsed time since midnight. Thus, instead of saying 3:45 p.m. one could say (time of day) 56.7 ks. There are exactly 86.4 ks in one day (each kilosecond being equivalent to 16 minutes and 40 seconds worth of conventional time). However, this nomenclature is rarely used in practice.
Scientific decimal time
Scientists often record time as decimal. For example, decimal days divide the day into 10 equal parts, and decimal years divide the year into 10 equal parts. Decimals are easier to plot than both (a) minutes and seconds, which uses the
sexagesimal
Sexagesimal, also known as base 60, is a numeral system with 60 (number), sixty as its radix, base. It originated with the ancient Sumerians in the 3rd millennium BC, was passed down to the ancient Babylonians, and is still used—in a modified fo ...
numbering system, (b) hours, months and days, which has irregular month lengths. In astronomy, the so-called
Julian day
The Julian day is a continuous count of days from the beginning of the Julian period; it is used primarily by astronomers, and in software for easily calculating elapsed days between two events (e.g., food production date and sell by date).
Th ...
uses decimal days centered on Greenwich noon.
;Seconds in a decimal minute
Since there are 60 seconds in a minute, a tenth part represents = 6 seconds.
;Minutes in a decimal hour
Since there are 60 minutes in an hour, a tenth part represents = 6 minutes.
;Hours in a decimal day
Since there are 24 hours in a day, a tenth part represents = 2.4 hours (2 hours and 24 minutes).
;Length of a decimal year
Since there are about 365 days in a year, there are about = 36.5 days in a tenth of a year. Hence the year 2020.5 represents the day 2 July 2020.
[ ] More exactly, a
"Julian year" is exactly 365.25 days long, so a tenth of the year is 36.525 days (36 days, 12 hours, 36 minutes).
These values, based on the Julian year, are most likely to be those used in astronomy and related sciences. A
Gregorian year, which takes into account the 100 vs. 400 leap year exception rule of the
Gregorian calendar
The Gregorian calendar is the calendar used in most parts of the world. It went into effect in October 1582 following the papal bull issued by Pope Gregory XIII, which introduced it as a modification of, and replacement for, the Julian cale ...
, is 365.2425 days (the average length of a year over a 400–year cycle), resulting in 0.1 years being a period of 36.52425 days ( seconds; 36 days, 12 hours, 34 minutes, 55.2 seconds).
Other decimal times
Numerous individuals have proposed variations of decimal time, dividing the day into different numbers of units and subunits with different names. Most are based upon fractional days, so that one decimal time format may be easily converted into another, such that all the following are equivalent:
* 0.500 day
* 5 heures décimales
* @500.beats
Swatch Internet Time
Swatch Internet Time (or ) is a decimal time system introduced in 1998 by the Swatch corporation as part of the marketing campaign for their line of ".beat" watches. Those without a watch could use the Internet to view the current time on the wat ...
(
see above)
* 50.0 ''kes'' or ''cés'' (centidays)
* 500 millidays
* 50.0% time as a percentage of the day
* 12:00 standard time
Some decimal time proposals are based upon alternate units of metric time. The difference between metric time and decimal time is that metric time defines units for measuring
time interval, as measured with a
stopwatch, and decimal time defines the time of day, as measured by a clock. Just as standard time uses the metric time unit of the second as its basis, proposed decimal time scales may use alternative metric units.
In the fictional ''
Star Trek
''Star Trek'' is an American science fiction media franchise created by Gene Roddenberry, which began with the Star Trek: The Original Series, series of the same name and became a worldwide Popular culture, pop-culture Cultural influence of ...
'' universe, each
stardate increment represents one milliyear, with 78 years in 2401, counted from 2323. The decimal represents a fractional day. Thus, stardates are a composition of two types of decimal time. In 2023, 78 years earlier would be 1945.
See also
*
12-hour clock
The 12-hour clock is a time convention in which the 24 hours of the day are divided into two periods: a.m. (from Latin , translating to "before midday") and p.m. (from Latin , translating to "after midday"). Each period consists of 12&nb ...
*
24-hour clock
The modern 24-hour clock is the convention of timekeeping in which the day runs from midnight to midnight and is divided into 24 hours. This is indicated by the hours (and minutes) passed since midnight, from to , with as an option to indicate ...
*
Centesimal minute and second of arc
*
Decimal calendar
*
Hexadecimal time
*
List of unusual units of measurement
*
Metric time
*
Stardate
*
Unix time
Unix time is a date and time representation widely used in computing. It measures time by the number of non-leap seconds that have elapsed since 00:00:00 Coordinated Universal Time, UTC on 1 January 1970, the Unix Epoch (computing), epoc ...
References
Notes
Sources
* National Convention of the French Republic (1793
LE CALENDRIER RÉPUBLICAIN Textes officiels Décrets Relatifs à l'établissement de l'Ère Républicaine published by Philippe Chapelin 2002
* Sizes, Inc. (2000
Last revised 27 February 2004
* Herschel, John (1849)
Outlines of Astronomy' published by Gallica 1995
External links
Decimal Time by Kevin Gut - Website that shows the current decimal time and a converter to and from decimal timeMetric Clock by Paul Dunning / Shows the current local decimal timeDecimal Time Clock & Calendar
{{DEFAULTSORT:Decimal Time
Time measurement systems
Metrication
Metrication in France
Time
Time is the continuous progression of existence that occurs in an apparently irreversible process, irreversible succession from the past, through the present, and into the future. It is a component quantity of various measurements used to sequ ...
Time in astronomy
Units of time