Conversion factors and common units to be used for North American Cooperation on Energy Information

Energy products are measured in physical units by their mass, volume, and energy content.  The measurement units that are specific to an energy product and are employed at the point of measurement of the energy flow are often referred to as “original” or “natural” units. Crude oil, for example, is generally measured by its volume. For natural gas, densities change with pressures and temperatures, and therefore, it is important to use standardized volumes.

This guide identifies commonly used units of measurements for various product types, and their abbreviations. As much of the work under this trilateral effort requires comparing, and presenting energy information in a consistent manner, conversion factors to be used when moving between imperial and metric systems of measurement are presented. When required factors are not identified below, we recommend using those provided by the International Energy Agency and/or the International Recommendations for Energy Statistics (IRES)Footnote 1.

Prefixes and Equivalents

SI/Metric Imperial
k kilo M thousand 103
M mega MM million 106
G giga B billion 109
T tera T trillion 1012
P peta - quadrillion 1015


Common Units

Crude oil, natural gas liquids, and petroleum products

Abbreviation Description
L Litres
gal Gallons
bbl Barrels
b/d barrels per day
Mb thousand barrels
Mb/d thousand barrels per day
MMb million barrels
MMb/d million barrels per day
m3 cubic metre
m3/d cubic metres per day


Natural gas

Abbreviation Description
cf cubic feet
Mcf thousand cubic feet
Mcf/d thousand cubic feet per day
MMcf million cubic feet
MMcf/d million cubic feet per day
Bcf billion cubic feet
Bcf/d billion cubic feet per day
Tcf trillion cubic feet
m3 cubic metre
m3/d cubic metres per day
Btu British thermal units
MMBtu million British thermal units
Btu/cf British thermal units per cubic foot
MTPA million tonnes per annum (of LNG)
kPa kilo pascal
psi pound per square inch
psia / kPaa atmospheric pressure



Abbreviation Description
V Volt
kV Kilovolt
MW Megawatt
kWh kilowatt hour
MWh megawatt hour
GWh gigawatt hour
TWh terawatt hour

Common conversions

Conversion factors for volume


Input unit Output unit Multiply by
barrels (bbl) cubic metres (m3) 0.158987295
cubic metres (m3) barrels (bbl) 6.28981077
barrels (bbl) litres (l) 158.987295
litres (l) barrels (b) 0.00628981077
barrels (bbl) cubic feet (cf) 5.61458333
cubic feet (cf) barrels (bbl) 0.178107607
litres (l) cubic metres (m3) 0.00100000000
cubic metres (m3) litres (l) 1000.00000
litres (l) gallons (US gal) 0.264172052
gallons (US gal) litres (l) 3.78541178



The two common standardized volumes used internationally and for the purpose of this trilateral effort are:

cubic feet measured at 60°F (15.6°C) and 14.73 psia, and
cubic metres measured at 15°C and 101.325 kPaa.

Input unit Output unit Multiply by
cubic metres (m3) cubic feet (cf) 35.3146667
cubic feet (cf) cubic metres (m3) 0.0283168466
standard cubic metre (Sm3) normal cubic metre (Nm3) 0.948000000
normal cubic metre (Nm3) standard cubic metre (Sm3) 1.05500000

Note: Sm3 measured at 15°C and 101.325 kPa, Nm3 measured at 0°C and 101.325 kPa.


Liquefied natural gas (LNG)

Input unit Output unit Multiply by
cubic metres (m3) LNG cubic metres (m3) natural gas 615.000000
cubic metres (m3) natural gas cubic metres (m3) LNG 0.001626016
cubic metres (m3) LNG cubic feet (cf) natural gas 21,718.5200
cubic feet (cf) natural gas cubic metres (m3) LNG 0.000046044
million tonnes LNG billion cubic feet (bcf) natural gas 48.0279467
billion cubic feet (bcf) natural gas million tonnes LNG 0.0208212107
million tonnes LNG per year (MTPA) billion cubic feet natural gas per day (Bcf/d) 0.131584156
billion cubic feet natural gas per day (Bcf/d) Million tonnes LNG per year (MTPA) 7.59974192

Note: LNG conversion factors can vary with reference conditions and feed gas composition.


Conversion factors for pressure

Input unit Output unit Multiply by
kilopascal (kPa) pounds per square inch (psi) 0.145037738
pounds per square inch (psi) kilopascal (kPa) 6.89475729


Conversion factors for energy

Input unit Output unit Multiply by
British thermal unit (Btu) calories (cal) 251.995761
calories (cal) British thermal unit (Btu) 0.00396832072
British thermal unit (Btu) joules (J) 1055.05585
joules (J) British thermal unit (Btu) 0.000947817120
joules (J) calories (cal) 0.238845897
calories (cal) joules (J) 4.186800001
joules (J) watt-hour (Wh) 0.000277777778
watt-hour (Wh) joules (J) 3600.00000