Tonne of oil equivalent

The tonne of oil equivalent (toe) is a unit of energy defined as the amount of energy released by burning one tonne of crude oil. It is approximately 42 gigajoules or 11.630 megawatt-hours, although as different crude oils have different calorific values, the exact value is defined by convention; several slightly different definitions exist. The toe is sometimes used for large amounts of energy.

Multiples of the toe are used, in particular the megatoe (Mtoe, one million toe) and the gigatoe (Gtoe, one billion toe). A smaller unit of kilogram of oil equivalent (kgoe or koe) is also sometimes used denoting 1/1000 toe.


The International Energy Agency defines one tonne of oil equivalent (toe) to be equal to:[1]

Conversion into other units:

  • 1 toe = 7.33 barrels of oil equivalent (boe)[3]

Some other sources and publications use divergent definitions of toe, for example:

  • 1 toe = 10.7 gigacalories (Gcal) – using the thermochemical calorie[2]
  • 1 toe = 41.85 gigajoules (GJ)[4]
  • 1 toe = 44.769 gigajoules (GJ) – based on using thermochemical calorie (calth)[2]
  • 1 toe = 39,683,205.411 British thermal units (BTU)

Conversion factors

  • 1 barrel of oil equivalent (boe) contains approximately 0.136 toe (i.e. there are approximately 7.33 boe in a toe).[5]
  • 1 t diesel = 1.01 toe
  • 1 m3 diesel = 0.98 toe
  • 1 t petrol = 1.05 toe
  • 1 m3 petrol = 0.86 toe
  • 1 t biodiesel = 0.86 toe
  • 1 m3 biodiesel = 0.78 toe
  • 1 t bioethanol = 0.64 toe
  • 1 m3 bioethanol = 0.51 toe[6]
  • 1 MWh = 0.086 toe [7] (therefore 1 toe = 11630.0 kWh) [8]
  • At thermal power plants, 1 MWh is generated with 0.22 toe fuel or 0.39 MWh with 0.086 toe[9] (39% thermal to electrical conversion efficiency)

Tonne of oil equivalent should be used carefully when converting electrical units. For instance, BP's 2007 report used a factor of 38% efficiency (the average efficiency of OECD thermal generating units in 2006), or roughly 16 GJ per toe, when converting kilowatt-hours to toe.[10]

Derived units

For multiples of the tonne of oil equivalent, it is more usual to speak of millions of tonnes of oil equivalent and kilotonnes of oil equivalent (ktoe).

Multiple Name Symbol
103kilotonne of oil equivalentktoe
106megatonne of oil equivalentMtoe

See also

  • A Cubic Mile of Oil  Book about the unit of energy
  • Barrel of oil equivalent
  • Conversion of units  Comparison of various scales
  • Energy density  Energy per volume
  • TNT equivalent  Class of units of measurement for explosive energy a unit of energy almost exactly 0.1 tonnes of oil equivalent


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