Wikidata:Units

This is a page for giving whatever information is available about storing units in Wikidata. Beyond units, Wikidata needs to express similar concepts like numeric datatype, scientific notation, and descriptions of uncertainty in data.

Units list

Each unit (unit of measurement (Q47574)) is related to physical properties (physical quantity (Q107715)).

The SI units (SI base unit (Q223662)) are green colored.

Spatial dimensions

Length (length (Q36253))

Unit	With prefixes	Corresponding properties
metre (Q11573)	yottametre (Q10543042)	radius (P2120), vehicle range (P2073), wingspan (P2050), height (P2048), width (P2049), length (P2043), elevation above sea level (P2044), distance from river mouth (P2148), focal length (P2151)
	zettametre (Q3277915)
	exametre (Q3277907)
	petametre (Q3277919)
	terametre (Q3267417)
	gigametre (Q854546)
	megametre (Q1054140)
	myriametre (Q1970718)
	kilometre (Q828224)
	hectometre (Q844338)
	decametre (Q848856)
	decimetre (Q200323)
	centimetre (Q174728)
	millimetre (Q174789)
	micrometre (Q175821)
	nanometre (Q178674)
	picometre (Q192274)
	femtometre (Q208788)
	attometre (Q6003257)
	zeptometre (Q3270676)
	yoctometre (Q3221356)
parsec (Q12129)	gigaparsec (Q14916719)
	megaparsec (Q3773454)
	kiloparsec (Q11929860)
	attoparsec (Q15784325)
light-year (Q531)
light-second (Q909315)
astronomical unit (Q1811)
mile (Q253276)
foot (Q3710)
inch (Q218593)
thousandth of an inch (Q1165799)

Area (area (Q11500))

Unit	With prefixes	Corresponding properties
square metre (Q25343)	square kilometre (Q712226)	area (P2046), watershed area (P2053), wing area (P2112)
	square centimetre (Q2489298)
	square millimetre (Q2737347)
are (Q185078)	hectare (Q35852)

Volume (volume (Q39297))

Unit	With prefixes	Corresponding properties
cubic metre (Q25517)	cubic kilometre (Q4243638)	volume as quantity (P2234)
	cubic decimetre (Q2175964)
	cubic centimetre (Q1022113)
	cubic millimetre (Q3675550)
litre (Q11582)	hectolitre (Q2029519)
	decalitre (Q2637946)
	centilitre (Q1815100)
	millilitre (Q2332346)
	microlitre (Q2282891)
	picolitre (Q3902688)
	femtolitre (Q3312063)

Time (time (Q11471)) and frequency (frequency (Q11652))

Quantities with unit of time represent a duration or time interval. To use a value representing a point in time (e.g. a date), use of time value is recommended.

Time interval (time interval (Q186081))

Unit	With prefixes	Corresponding properties
second (Q11574)	millisecond (Q723733)	duration (P2047), half-life (P2114)
	microsecond (Q842015)
	nanosecond (Q838801)
	femtosecond (Q1777507)
	attosecond (Q2483628)
	picosecond (Q3902709)
day (Q573)
week (Q23387)
hour (Q25235)
minute (Q7727)
month (Q5151)
annum (Q1092296)
year (Q577)		term length of office (P2097)
24-hour clock time (Q216589)		Wikidata:Property_proposal/Pending/2#checkin_time_.28en.29

Frequency (frequency (Q11652))

Unit	With prefixes	Corresponding properties
hertz (Q39369)	kilohertz (Q2143992)	frequency (P2144)
	megahertz (Q732707)
	gigahertz (Q3276763)

Matter

Mass (mass (Q11423))

Unit	With prefixes	Corresponding properties
kilogram (Q11570)	yottagram (Q613726)	mass (P2067)
	zettagram (Q14754979)
	exagram (Q2655272)
	petagram (Q2612219)
	teragram (Q1770733)
	gigagram (Q2799294)
	megagram (Q11776930)
	myriagram (Q2151240)
	hectogram (Q1057069)
	decagram (Q6517513)
	gram (Q41803)
	decigram (Q1772386)
	centigram (Q2691798)
	milligram (Q3241121)
	microgram (Q1645498)
	nanogram (Q2282906)
	picogram (Q3239557)
	femtogram (Q1913097)
	attogram (Q2438073)
	zeptogram (Q6171168)
	yoctogram (Q6170164)
pound (Q100995)
dalton (Q483261)

Density (density (Q29539))

Unit	With prefixes	Corresponding properties
kilogram per cubic metre (Q844211)	gram per cubic centimetre (Q13147228)	density (P2054)

Concentration (concentration (Q3686031))

Unit	Corresponding properties
gram per litre (Q834105)	solubility (P2177), lower flammable limit (P2202), upper flammable limit (P2203), median lethal dose (LD50) (P2240), minimal lethal dose (P2300) and time-weighted average exposure limit (P2404), ceiling exposure limit (P2405), maximum peak exposure limit (P2406) and short-term exposure limit (P2407)
Gram per cubic meter
millilitre per litre (Q21075844)
milligram per cubic metre (Q21077820)
mol per kilogram of solvent (Q21064838)
mole per litre (Q21064845)
mass fraction (Q899138)
mass percentage (Q110162802)
amount-of-substance fraction (Q125264)
volume fraction (Q909482)
parts per million (Q21006887)
part per billion (Q2055118)
milligram per kilogram (Q21091747)
gram per kilogram (Q21061369)

Thermodynamics

Temperature (temperature (Q11466))

Unit	Corresponding properties
degree Celsius (Q25267)	temperature (P2076), melting point (P2101), boiling point (P2102), decomposition point (P2107), sublimation temperature (P2113), flash point (P2128)
kelvin (Q11579)
degree Fahrenheit (Q42289)
Rankine scale (Q207488)

Pressure (pressure (Q39552))

Unit	With prefixes	Corresponding properties
standard atmosphere (Q177974)		under pressure (P2077), vapor pressure (P2119)
technical atmosphere (Q909066)
bar (Q103510)
pascal (Q44395)	megapascal (Q21062777)
	kilopascal (Q21064807)
	hectopascal (Q5139563)
torr (Q185648)
millimetre of mercury (Q6859652)
metre of water (Q2042279)	centimetre of water (Q1247300)
	millimetre of water (Q13479685)

Thermal capacity (heat capacity (Q179388))

Unit	With prefixes	Corresponding properties
joule per mole kelvin (Q20966455)		specific heat capacity (P2056)

Thermal conductivity (thermal conductivity (Q487005))

Unit	With prefixes	Corresponding properties
watt per metre kelvin (Q1463969)		thermal conductivity (P2068)

Mechanics

Speed (speed (Q3711325))

Unit	With prefixes	Corresponding properties
kilometre per hour (Q180154)		speed (P2052), speed of sound (P2075)
metre per second (Q182429)	kilometre per second (Q4220561)
knot (Q128822)

Kinematic viscosity (kinematic viscosity (Q15106259))

Unit	With prefixes	Corresponding properties
stokes (Q1569733)		kinematic viscosity (P2118)
square metre per second (Q3332099)

Electromagnetism, optics

Electrical conductivity (electrical conductivity (Q4593291))

Unit	With prefixes	Corresponding properties
ampere per volt metre (Q20966435)		electrical conductivity (P2055)

Luminosity (luminosity (Q105902))

Unit	With prefixes	Corresponding properties
solar luminosity (Q843877)		luminosity (P2060)

Chemistry

Enthalpy (enthalpy (Q161064))

Unit	With prefixes	Corresponding properties
joule per mole (Q13035094)	kilojoule per mole (Q752197)	molar fusion enthalpy (P2066), molar enthalpy of vaporization (P2116), combustion enthalpy (P2117)
kilojoule per kilogram (Q21077849)

Currency (currency (Q8142))

Unit	With prefixes	Corresponding properties
Euro (Q4916)		award received (P166), prize money (P2121), cost (P2130), nominal GDP (P2131), nominal GDP per capita (P2132), total debt (P2133), total reserves (P2134), total exports (P2135), total imports (P2136), total equity (P2137), total liabilities (P2138), total revenue (P2139), foreign direct investment net outflow (P2140), foreign direct investment net inflow (P2141), box office (P2142), household wealth (P2220)
crore (Q1137675)

Dimensionless

Item	Corresponding properties
infection (Q166231)	number of cases (P1603)

Reports

• Wikidata:Database reports/Units of measurements
• Wikidata:Database reports/Items with unit symbol
• Special:ListProperties/quantity
• Subclasses of "unit of measurement" (Q47574)
• Properties with Constraint:Units

• Wikidata:Database reports/List of properties with Constraint:Unit templates and their values

Discussion list

Please add any discussions on this topic to this list -

Tracked in Phabricator
Task T77977

• Wikidata:Requests for comment/Dimensions and units for the quantity datatype - proposal for which units should be implemented first for the 'number with unit' datatype.
• See the Phabricator tasks at right, and this one
• Wikidata:Project_chat/Archive/2014/09#Quantities_with_units
• Wikidata:Project_chat/Archive/2015/05#Open_for_SI-unit_properties
• Wikidata:Project_chat/Archive/2015/06#Unit-based_properties_-_a_work-around
• Wikidata:Property_proposal/Property_metadata#units_used_for_this_property
• Wikidata:Property_proposal/Generic#conversion_to_standard_unit
• Wikidata:Property_proposal/Generic#standard_unit
• Wikidata:Property_proposal/Generic#conversion_to_SI_base_unit
• "Units are live! \o/" mailing list announcement