Energy unit converter
Convert any energy quantity to and from the units engineers actually use.
Ionect energy unit converterThe Ionect energy unit converter converts any energy quantity across the units engineers and academics use, from joules and kilowatt-hours to gigajoules, BTU, therms, tonnes of oil equivalent, and barrels of oil equivalent. It also shows the equivalent quantity of common fuels and explains each unit.
SI and metric
Watt-hours
Calorie-based
Imperial and thermal
Fuel-equivalent energy units
Scientific and other
Fuel-equivalent context
Energy-content equivalents on a Lower Heating Value basis, not efficiency-adjusted.
Definitions and conventions
- toe
- Tonne of oil equivalent: the energy released by burning one tonne of crude oil, standardised by the IEA to exactly 41.868 GJ. Used to compare fuels and national energy balances.
- tce
- Tonne of coal equivalent: a standardised 29.3076 GJ, the IEA reference for one tonne of hard coal.
- boe
- Barrel of oil equivalent: about 6.12 GJ, roughly the energy in one 159-litre barrel of crude oil. Common in the oil and gas industry.
- therm
- Therm: 105.506 MJ, used for natural gas billing. One therm is about 100 cubic feet of natural gas.
- BTU and MMBtu
- British thermal unit: the energy to heat one pound of water by 1 degree Fahrenheit, about 1055 J. MMBtu is one million BTU, the standard unit in gas trading.
- quad
- Quad: one quadrillion (1e15) BTU, used for national and global energy statistics.
- Wh vs J
- A watt-hour is power times time. 1 Wh = 3600 J, and 1 kWh = 3.6 MJ.
- calorie
- This tool uses the thermochemical calorie (4.184 J). The international-table calorie (4.1868 J) differs by less than 0.07 percent.
Conversions use standard physical constants and IEA conventions. See also the hydrogen unit converter, CO₂ emissions calculator, green hydrogen calculator and e-fuel cost estimator.
Frequently asked questions
How many GJ in 1 MWh?
3.6 GJ.
How many kWh in 1 GJ?
277.78 kWh.
What is a tonne of oil equivalent (toe)?
41.868 GJ, the IEA standard for one tonne of crude oil.
What is a therm?
105.506 MJ, used for natural gas billing, about 100 cubic feet of gas.
What is the difference between BTU and MMBtu?
MMBtu is one million BTU, the standard gas-trading unit; 1 MMBtu is about 1.055 GJ.
How many BTU in 1 kWh?
About 3412 BTU.
What is a barrel of oil equivalent (boe)?
About 6.12 GJ, roughly the energy in one 159-litre barrel of crude.
How much natural gas equals 1 MWh?
About 100 Nm³ at 36 MJ/Nm³ LHV, energy-content basis.