toe

tonne of oil equivalent

Energyexact by definition

The tonne of oil equivalent is defined as exactly 10⁷ International Table kilocalories, which is exactly 41.868 gigajoules. It is not a measurement of any actual oil but a conventional accounting unit, used by the IEA and national statistical agencies so that coal, gas, hydro and nuclear can be added together on one line.

Watch out: Real crude varies by several percent around this figure, so a toe is a bookkeeping unit rather than a physical property of a barrel. Related conventions include the barrel of oil equivalent, about 5.8 million BTU, and the tonne of coal equivalent at exactly 7 × 10⁶ kcal. Converting between energy statistics published on different conventions is a known source of quiet error.

1 toe 41,868,000,000 J