Units of measure and quantities

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Last UpdatedSep 09, 2025
12 minute read

The Sequential Data Store (SDS) provides a collection of built-in units of measure (UOM). These units of measure can be associated with streams and types to provide unit information for stream data that model measurable quantities. If data has unit information associated with it, SDS supports unit conversions when retrieving data. For more information, see Reading data.

Because a UOM (meter, for example) defines the magnitude of a quantity (for example, length), SDS represents this by way of two objects: SdsUom and SdsUomQuantity.

SdsUom

SdsUom represents a single unit of measure, such as 'meter'.

The following table lists the required and optional SdsUom fields.

Property	Type	Optionality	Details	Example
Id	String	Required	Unique identifier for the unit of measure.	meters per second
Abbreviation	String	Optional	Abbreviation for the unit of measure.	m/s
Name	String	Optional	Full name for the unit of measure.	Meters per second
DisplayName	String	Optional	Friendly display name for the unit of measure.	meters per second
QuantityId	String	Required	The identifier associated with the quantity that this unit is a measure of.	Velocity
ConversionFactor	Double	Required	Used for unit conversions. When a value of this unit is multiplied by the ConversionFactor and then incremented by the ConversionOffset, the value in terms of the base unit of the corresponding quantity is returned.	1.0
ConversionOffset	Double	Required	Used for unit conversions. See details for ConversionFactor.	0.0
CreatedDate	DateTime	Set by server	Timestamp in ISO 8601 extended format and UTC time standard when the SdsUom was created. Cannot be modified by users.	0001-01-01T00:00:00Z
ModifiedDate	DateTime	Set by server	Timestamp in ISO 8601 extended format and UTC time standard when the SdsUom was last modified. Cannot be modified by users.	0001-01-01T00:00:00Z

SdsUomQuantity

SdsUomQuantity represents a single measurable quantity (for example, length).

The following table shows the required and optional SdsUomQuantity fields.

Property	Type	Optionality	Details	Example
Id	String	Required	Unique identifier for the quantity.	Velocity
Name	String	Optional	Full name for the quantity.	Velocity
BaseUom	SdsUom	Required	The base unit of measure for this quantity. All other Uom's measuring this quantity will have ConversionFactor's and ConversionOffsets relative to the BaseUom.	SdsUom representing "meters per second"
Dimensions	short[]	Optional	Reserved for internal use. Represents the seven base SI dimensions: Length, Mass, Time, Electric Current, Thermodynamic Temperature, Amount of Substance, and Luminous Density.	[1,0,-1,0,0,0,0]
CreatedDate	DateTime	Set by server	Timestamp in ISO 8601 extended format and UTC time standard when the SdsUomQuantity was created. Cannot be modified by users.	0001-01-01T00:00:00Z
ModifiedDate	DateTime	Set by server	Timestamp in ISO 8601 extended format and UTC time standard when the SdsUomQuantity was last modified. Cannot be modified by users.	0001-01-01T00:00:00Z

Supported system-defined unit quantities

Supported quantities and their base units of measure are listed below. Supported quantities are read-only.

Quantity Id	Base Uom Id
Acceleration	meter per square second
Angular Velocity	radian per second
Area	square meter
Computer Storage	byte
Conductivity	siemens per meter
Density	kilogram per cubic meter
Dynamic Viscosity	pascal second
Electric Charge	coulomb
Electric Current	ampere
Electric Potential	volt
Electric Resistance	ohm
Energy	joule
Energy per Length	joule per meter
Entropy and Heat Capacity	joule per kelvin
Force	newton
Frequency	hertz
Illuminance	lux
Irradiance	watt per square meter
Length	meter
Luminous Intensity	candela
Mass	kilogram
Mass Flow Rate	kilogram per second
Molar Flow Rate	mole per second
Molecular Weight	kilogram per mole
Amount of Substance	mole
Plane Angle	radian
Power	watt
Pressure	pascal
Quantity	count
Quantity per Volume	count per cubic meter
Ratio	percent
Reciprocal length	inverse meter
Specific Energy	joule per kilogram
Specific Entropy and Specific Heat Capacity	joule per kilogram kelvin
Specific Volume	cubic meter per kilogram
Speed	meter per second
Temperature	kelvin
Temperature (Delta)	delta kelvin
Time	second
Volume	cubic meter
Volume Flow Rate	cubic meter per second

Supported system-defined units of measure

Supported units of measure are listed below. Supported units of measure are read-only.

Uom ID	Uom Name	Uom Abbrev	Quantity ID	Conversion Factor	Conversion Offset
count	count	count	Quantity	1	0
Ampere hour	Ampere hour	Ah	Electric Charge	3600	0
coulomb	coulomb	C	Electric Charge	1	0
kilogram per second	kilogram per second	kg/s	Mass Flow Rate	1	0
long ton per day	long ton per day	lton/d	Mass Flow Rate	0.011759802	0
million pound per day	million pound per day	MMlb/d	Mass Flow Rate	5.24991169	0
short ton per day	short ton per day	ston/d	Mass Flow Rate	0.010499823	0
thousand pound per day	thousand pound per day	klb/d	Mass Flow Rate	0.005249912	0
gram per second	gram per second	g/s	Mass Flow Rate	0.001	0
pound per second	pound per second	lb/s	Mass Flow Rate	0.45359237	0
tonne per day	tonne per day	t/d	Mass Flow Rate	0.0115740740740741	0
long ton	long ton	lton	Mass	1016.046909	0
million pound	million pound	MM lb	Mass	453592.37	0
ounce	ounce	oz	Mass	0.028349523	0
short ton	short ton	ston	Mass	907.18474	0
thousand pound	thousand pound	klb	Mass	453.59237	0
ton	ton	ton	Mass	907.18474	0
gram	gram	g	Mass	0.001	0
milligram	milligram	mg	Mass	1.00E-06	0
pound	pound	lb	Mass	0.45359237	0
tonne	tonne	t	Mass	1000	0
kilogram	kilogram	kg	Mass	1	0
second	second	s	Time	1	0
hour	hour	h	Time	3600	0
day	day	d	Time	86400	0
month	month	month	Time	2628000	0
week	week	week	Time	604800	0
year	year	yr	Time	31536000	0
minute	minute	min	Time	60	0
dyne	dyne	dyne	Force	1.00E-05	0
kilogram-force	kilogram-force	kgf	Force	9.80665	0
pound-force	pound-force	lbf	Force	4.44822161526	0
newton	newton	N	Force	1	0
watt	watt	W	Power	1	0
million British thermal unit per day	million British thermal unit per day	MM Btu/d	Power	12211.29459	0
million British thermal unit per hour	million British thermal unit per hour	MM Btu/h	Power	293071.0702	0
gigawatt	gigawatt	GW	Power	1000000000	0
megawatt	megawatt	MW	Power	1000000	0
British thermal unit per hour	British thermal unit per hour	Btu/h	Power	0.29307107017222	0
calorie per second	calorie per second	cal/s	Power	4.1868	0
horsepower	horsepower	hp	Power	745.699871582	0
joule per second	joule per second	J/s	Power	1	0
kilowatt	kilowatt	kW	Power	1000	0
megajoule per hour	megajoule per hour	MJ/h	Power	277.777777777778	0
million calorie per hour	million calorie per hour	MMcal/h	Power	1163	0
mole per second	mole per second	mol/s	Molar Flow Rate	1	0
gram mole per second	gram mole per second	gmol/s	Molar Flow Rate	1	0
kilogram mole per second	kilogram mole per second	kmol/s	Molar Flow Rate	1000	0
pound mole per second	pound mole per second	lbmol/s	Molar Flow Rate	453.59237	0
meter	meter	m	Length	1	0
centimeter	centimeter	cm	Length	0.01	0
inch	inch	in	Length	0.0254	0
International nautical mile	International nautical mile	nmi	Length	1852	0
kilometer	kilometer	km	Length	1000	0
millimeter	millimeter	mm	Length	0.001	0
foot	foot	ft	Length	0.3048	0
mile	mile	mi	Length	1609.344	0
sixteenth of an inch	sixteenth of an inch	sxi	Length	0.0015875	0
yard	yard	yd	Length	0.9144	0
micrometer	micrometer	μm	Length	0.000001	0
nanometer	nanometer	nm	Length	0.000000001	0
candela	candela	cd	Luminous Intensity	1	0
meter per second	meter per second	m/s	Speed	1	0
centimeter per second	centimeter per second	cm/s	Speed	0.01	0
foot per second	foot per second	ft/s	Speed	0.3048	0
International nautical mile per hour	International nautical mile per hour	nmi/h	Speed	0.514444444444444	0
kilometer per hour	kilometer per hour	km/h	Speed	0.277777777777778	0
mile per hour	mile per hour	mi/h	Speed	0.44704	0
revolution per minute	revolution per minute	rpm	Angular Velocity	0.10471975511966	0
radian per second	radian per second	rad/s	Angular Velocity	1	0
barrel per day	barrel per day	bbl/d	Volume Flow Rate	1.84013072833333E-06	0
cubic centimeter per second	cubic centimeter per second	cm3/s	Volume Flow Rate	1.00E-06	0
cubic foot per second	cubic foot per second	ft3/s	Volume Flow Rate	0.028316846592	0
cubic meter per hour	cubic meter per hour	m3/h	Volume Flow Rate	0.000277777777777778	0
Imperial gallon per minute	Imperial gallon per minute	Imp gal/min	Volume Flow Rate	7.57681666666663E-05	0
liter per second	liter per second	L/s	Volume Flow Rate	0.001	0
US gallon per minute	US gallon per minute	US gal/min	Volume Flow Rate	6.30901964E-05	0
cubic meter per second	cubic meter per second	m3/s	Volume Flow Rate	1	0
cubic foot per minute	cubic foot per minute	ft3/min	Volume Flow Rate	0.000471947443	0
pascal	pascal	Pa	Pressure	1	0
atmosphere	atmosphere	atm	Pressure	101325	0
bar	bar	bar	Pressure	100000	0
inches of mercury	inches of mercury	inHg	Pressure	3386.38815789	0
kilogram-force per square centimeter	kilogram-force per square centimeter	kgf/cm2	Pressure	98066.5	0
kilogram-force per square meter	kilogram-force per square meter	kgf/m2	Pressure	9.80665	0
kilopascal	kilopascal	kPa	Pressure	1000	0
millimeter of mercury	millimeter of mercury	mmHg	Pressure	133.322368421	0
newton per square meter	newton per square meter	N/m2	Pressure	1	0
pound-force per square inch	pound-force per square inch	psi	Pressure	6894.75729316836	0
pound-force per square inch (customary)	pound-force per square inch (customary)	psia	Pressure	6894.75729316836	0
torr	torr	torr	Pressure	133.322368421	0
hectopascal	hectopascal	hPa	Pressure	100	0
millibar	millibar	mbar	Pressure	100	0
square meter	square meter	m2	Area	1	0
square foot	square foot	ft2	Area	0.09290304	0
acre	acre	acre	Area	4046.856422	0
square mile	square mile	mi2	Area	2589988.11	0
square yard	square yard	yd2	Area	0.83612736	0
hectare	hectare	ha	Area	10000	0
square centimeter	square centimeter	cm2	Area	0.0001	0
square inch	square inch	in2	Area	0.00064516	0
square kilometer	square kilometer	km2	Area	1000000	0
square millimeter	square millimeter	mm2	Area	1.00E-06	0
yobibyte	yobibyte	YiB	Computer Storage	1.21E+24	0
zebibyte	zebibyte	ZiB	Computer Storage	1.18E+21	0
exbibyte	exbibyte	EiB	Computer Storage	1.15E+18	0
pebibyte	pebibyte	PiB	Computer Storage	1.13E+15	0
tebibyte	tebibyte	TiB	Computer Storage	1.10E+12	0
gibibyte	gibibyte	GiB	Computer Storage	1073741824	0
mebibyte	mebibyte	MiB	Computer Storage	1048576	0
kibibyte	kibibyte	KiB	Computer Storage	1024	0
yottabyte	yottabyte	YB	Computer Storage	1.00E+24	0
zettabyte	zettabyte	ZB	Computer Storage	1.00E+21	0
exabyte	exabyte	EB	Computer Storage	1.00E+18	0
petabyte	petabyte	PB	Computer Storage	1.00E+15	0
terabyte	terabyte	TB	Computer Storage	1.00E+12	0
gigabyte	gigabyte	GB	Computer Storage	1000000000	0
megabyte	megabyte	MB	Computer Storage	1000000	0
kilobyte	kilobyte	kB	Computer Storage	1000	0
byte	byte	B	Computer Storage	1	0
kelvin	kelvin	K	Temperature	1	0
degree Celsius	degree Celsius	°C	Temperature	1	273.15
degree Rankine	degree Rankine	°R	Temperature	0.555555556	-2.56E-13
degree Fahrenheit	degree Fahrenheit	°F	Temperature	0.555555555555556	255.3722222
milliampere	milliampere	mA	Electric Current	0.001	0
ampere	ampere	A	Electric Current	1	0
joule per gram	joule per gram	J/g	Specific Energy	1000	0
joule per kilogram	joule per kilogram	J/kg	Specific Energy	1	0
British thermal unit per pound	British thermal unit per pound	Btu/lb	Specific Energy	2326	0
kilocalorie per kilogram	kilocalorie per kilogram	kcal/kg	Specific Energy	4186.8	0
kilojoule per kilogram	kilojoule per kilogram	kJ/kg	Specific Energy	1000	0
kilojoule per pound	kilojoule per pound	kJ/lb	Specific Energy	2204.62262184878	0
British thermal unit per degree Rankine	British thermal unit per degree Rankine	Btu/°R	Entropy and Heat Capacity	1899.100534716	0
British thermal unit per degree Fahrenheit	British thermal unit per degree Fahrenheit	Btu/°F	Entropy and Heat Capacity	1899.100534716	0
kilojoule per kelvin	kilojoule per kelvin	kJ/K	Entropy and Heat Capacity	1000	0
joule per kelvin	joule per kelvin	J/K	Entropy and Heat Capacity	1	0
cubic foot per pound	cubic foot per pound	ft3/lb	Specific Volume	0.0624279605761446	0
cubic centimeter per gram	cubic centimeter per gram	cm3/g	Specific Volume	0.001	0
cubic meter per kilogram	cubic meter per kilogram	m3/kg	Specific Volume	1	0
hertz	hertz	Hz	Frequency	1	0
mole	mole	mol	Amount of Substance	1	0
gram mole	gram mole	gmol	Amount of Substance	1	0
kilogram mole	kilogram mole	kmol	Amount of Substance	1000	0
pound mole	pound mole	lbmol	Amount of Substance	453.59237	0
percent	percent	%	Ratio	1	0
decimal	decimal	decimal	Ratio	100	0
parts per billion	parts per billion	ppb	Ratio	1.00E-07	0
parts per million	parts per million	ppm	Ratio	0.0001	0
ohm	ohm	Ω	Electric Resistance	1	0
gram per gram mole	gram per gram mole	g/gmol	Molecular Weight	0.001	0
pound per pound mole	pound per pound mole	lb/lbmol	Molecular Weight	0.001	0
kilogram per mole	kilogram per mole	kg/mol	Molecular Weight	1	0
kilogram per kilogram mole	kilogram per kilogram mole	kg/kmol	Molecular Weight	0.001	0
British thermal unit per pound degree Rankine	British thermal unit per pound degree Rankine	Btu/(lb °R)	Specific Entropy and Specific Heat Capacity	4186.8	0
British thermal unit per pound degree Fahrenheit	British thermal unit per pound degree Fahrenheit	Btu/(lb °F)	Specific Entropy and Specific Heat Capacity	4186.8	0
joule per gram kelvin	joule per gram kelvin	J/(g K)	Specific Entropy and Specific Heat Capacity	1000	0
kilojoule per kilogram kelvin	kilojoule per kilogram kelvin	kJ/(kg K)	Specific Entropy and Specific Heat Capacity	1000	0
joule per kilogram kelvin	joule per kilogram kelvin	J/(kg K)	Specific Entropy and Specific Heat Capacity	1	0
kilovolt	kilovolt	kV	Electric Potential	1000	0
millivolt	millivolt	mV	Electric Potential	0.001	0
megavolt	megavolt	MV	Electric Potential	1000000	0
volt	volt	V	Electric Potential	1	0
joule	joule	J	Energy	1	0
gigawatt hour	gigawatt hour	GWh	Energy	3.60E+12	0
megawatt hour	megawatt hour	MWh	Energy	3600000000	0
watt hour	watt hour	Wh	Energy	3600	0
milliwatt hour	milliwatt hour	mWh	Energy	3.60	0
British thermal unit	British thermal unit	Btu	Energy	1055.05585262	0
calorie	calorie	cal	Energy	4.1868	0
gigajoule	gigajoule	GJ	Energy	1000000000	0
kilojoule	kilojoule	kJ	Energy	1000	0
kilowatt hour	kilowatt hour	kWh	Energy	3600000	0
megajoule	megajoule	MJ	Energy	1000000	0
watt second	watt second	Ws	Energy	1	0
kilocalorie	kilocalorie	kcal	Energy	4186.8	0
million calorie	million calorie	MMcal	Energy	4186800	0
million British thermal unit	million British thermal unit	MM Btu	Energy	1055055853	0
newton meter	newton meter	Nm	Energy	1	0
acre foot	acre foot	acre ft	Volume	1233.481838	0
million imperial gallon	million imperial gallon	Imp Mgal	Volume	4546.09	0
thousand imperial gallon	thousand imperial gallon	Imp kgal	Volume	4.54609	0
barrel	barrel	bbl	Volume	0.158987295	0
Imperial gallon	Imperial gallon	Imp gal	Volume	0.00454609	0
million US gallon	million US gallon	US Mgal	Volume	3785.411784	0
thousand US gallon	thousand US gallon	US kgal	Volume	3.785411784	0
cubic centimeter	cubic centimeter	cm3	Volume	1.00E-06	0
cubic foot	cubic foot	ft3	Volume	0.028316846592	0
kiloliter	kiloliter	kL	Volume	1	0
liter	liter	L	Volume	0.001	0
megaliter	megaliter	M L	Volume	1000	0
milliliter	milliliter	mL	Volume	1.00E-06	0
thousand cubic meter	thousand cubic meter	k m3	Volume	1000	0
US gallon	US gallon	US gal	Volume	0.003785411784	0
million barrel	million barrel	MMbbl	Volume	158987.2949	0
thousand barrel	thousand barrel	kbbl	Volume	158.9872949	0
cubic meter	cubic meter	m3	Volume	1	0
kilogram per cubic meter	kilogram per cubic meter	kg/m3	Density	1	0
gram per liter	gram per liter	g/L	Density	1	0
kilogram per liter	kilogram per liter	kg/L	Density	1000	0
pound per barrel	pound per barrel	lb/bbl	Density	2.85301017421182	0
pound per cubic foot	pound per cubic foot	lb/ft3	Density	16.0184633739601	0
pound per US gallon	pound per US gallon	lb/US gal	Density	119.826427316897	0
tonne per cubic meter	tonne per cubic meter	t/m3	Density	1000	0
microgram per cubic meter	microgram per cubic meter	µg/m3	Density	1.0E-9	0
radian	radian	rad	Plane Angle	1	0
degree	degree	°	Plane Angle	0.0174532925199433	0
revolution	revolution	r	Plane Angle	6.28318530717959	0
pascal second	pascal second	Pa*s	Dynamic Viscosity	1	0
poise	poise	P	Dynamic Viscosity	0.1	0
delta degree Fahrenheit	delta degree Fahrenheit	delta °F	Temperature (Delta)	0.555555555555556	0
delta degree Rankine	delta degree Rankine	delta °R	Temperature (Delta)	0.555555555555556	0
delta kelvin	delta kelvin	delta K	Temperature (Delta)	1	0
delta degree Celsius	delta degree Celsius	delta °C	Temperature (Delta)	1	0
millimeter per square second	millimeter per square second	mm/s2	Acceleration	0.001	0
meter per square second	meter per square second	m/s2	Acceleration	1	0
decisiemens per meter	decisiemens per meter	dS/m	Conductivity	0.1	0
siemens per meter	siemens per meter	S/m	Conductivity	1	0
microsiemens per centimeter	microsiemens per centimeter	µS/cm	Conductivity	0.0001	0
count per liter	count per liter	Count/L	Quantity per Volume	0.001	0
count per cubic meter	count per cubic meter	Count/m3	Quantity per Volume	1	0
watt-hours per mile	watt-hours per mile	Wh/mi	Energy per Length	0.44704	0
joule per meter	joule per meter	J/m	Energy per Length	1	0
inverse centimeter	inverse centimeter	cm-1	Reciprocal Length	100	0
inverse meter	inverse meter	m-1	Reciprocal Length	1	0
lux	lux	Lx	Illuminance	1	0
watt per square meter	watt per square meter	W/m2	Irradiance	1	0
cubic meter per day	cubic meter per day	m3/d	Volume Flow Rate	1.15740740740741E-05	0
thousand barrels per day	thousand barrels per day	kbbl/d	Volume Flow Rate	0.0018401307289352	0
meter per minute	meter per minute	m/min	Speed	0.0166666666666667	0
pound per day	pound per day	lb/d	Mass Flow Rate	5.249912E-06	0
Imperial gallon per day	Imperial gallon per day	Imp gal/d	Volume Flow Rate	5.261678240740741E-08	0
US gallon per day	US gallon per day	US gal/d	Volume Flow Rate	4.381263638888889E-08	0
liter per day	liter per day	l/d	Volume Flow Rate	1.15740740740741E-08	0
liter per minute	liter per minute	l/min	Volume Flow Rate	1.66666666666667E-05	0
liter per hour	liter per hour	l/h	Volume Flow Rate	2.77777777777778E-07	0
thousand US gallon per hour	thousand US gallon per hour	US kgal/h	Volume Flow Rate	0.00105150327333333	0
thousand US gallon per minute	thousand US gallon per minute	US kgal/min	Volume Flow Rate	0.0630901964	0
thousand Imperial gallon per hour	thousand Imperial gallon per hour	Imp kgal/h	Volume Flow Rate	0.00126280277777778	0
thousand Imperial gallon per minute	thousand Imperial gallon per minute	Imp kgal/min	Volume Flow Rate	0.0757681666666667	0
cubic foot per hour	cubic foot per hour	ft3/h	Volume Flow Rate	7.86579072000000E-06	0
bushel	bushel	bu	Volume	0.03523907016688	0
kilogram per hour	kilogram per hour	kg/h	Mass Flow Rate	0.000277777777777778	0
kilojoule per hour	kilojoule per hour	kJ/h	Power	0.277777777777778	0
gram per cubic meter	gram per cubic meter	g/m3	Density	0.001	0
millimeter per second	millimeter per second	mm/s	Speed	0.001	0

Associating a unit of measure with a type

At type creation, you can associate SdsUom with a SdsTypeProperty.

Associating a unit of measure with a stream

At stream creation, you can override any unit of measure associated with an SdsTypeProperty belonging to the type of the stream. This override enables the reuse of a type that may have default unit information associated with it already. For more information, see SdsStreamPropertyOverride.

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