British thermal units to kilowatt-hours – and kilowatt-hours to British thermal units

Formula

Multiply the value in British thermal units by 0.00029307107 to get kilowatt-hours.
kWh = BTU × 0.00029307107

Multiply the value in kilowatt-hours by 3,412.1416 to get British thermal units.
BTU = kWh × 3,412.1416

How to convert British thermal units to kilowatt-hours

Type a value in the field above and the result is calculated instantly. Use the arrow button to swap direction, or pick other units from the lists.

About the units

British thermal units. The British thermal unit comes in several variants up to 0.5% apart. This conversion uses the international table Btu, exactly 1,055.05585262 joules; the thermochemical variant is 0.067% smaller. The Btu is the general energy unit in the US – a gallon of petrol is around 120,000 Btu and a therm exactly 100,000 – but it is absent from the EU units directive. The commonest trap is air conditioning: “12,000 Btu” means Btu per hour, a power, and differs from the energy by a factor of 3,600.

Kilowatt-hours. A kilowatt-hour is the energy of one kilowatt for one hour, exactly 3.6 megajoules. It needs no definition of its own: the watt and the hour are both legal units in the EU, and combinations of legal units are legal too. It is the unit on the electricity bill and on the EU energy label, where a fridge’s annual consumption is given as a whole number of kilowatt-hours per year. The trap is kW against kWh: the kilowatt is power, the kilowatt-hour energy.