Tonne of oil equivalent (toe)

The tonne of oil equivalent is defined by the IEA and OECD as exactly 10⁷ kilocalories (International Table), approximately the net heat content of one tonne of crude oil. Real crudes vary between roughly 40 and 45 GJ/t, so toe is a convention, not a physical measurement of a particular oil.

The IEA World Energy Balances and Eurostat report energy supply and consumption in Mtoe and ktoe (Eurostat also in TJ). The EU's efficiency targets under the Energy Efficiency Directive (EU) 2023/1791 are expressed in Mtoe: final energy consumption of no more than 763 Mtoe in 2030. China often uses tonnes of coal equivalent instead.

Converting electricity to toe requires choosing a method: 1 MWh = 0.086 toe under physical energy content, while older conventions applied a fossil-substitution efficiency (for example 0.086 / 0.38 ≈ 0.22 toe per MWh). Per-capita energy use is commonly cited as toe/person: roughly 6.5–7 in the United States, 3 in the EU, 2.5 in China and below 0.5 in much of sub-Saharan Africa.