About the kWh to BTU Converter
This kWh to BTU converter turns kilowatt-hours of energy into British thermal units, therms and megajoules — and works in reverse from any of those units. It is useful when comparing an electric bill (billed in kWh) with a gas bill (billed in therms or BTU), sizing heating equipment, or reading furnace, boiler and heat-pump specs that mix the two systems.
One kilowatt-hour is about 3,412 BTU, and one therm is 100,000 BTU, or roughly 29.3 kWh. Enter your monthly usage from either bill to see the equivalent energy in the other unit.
This is a pure energy conversion. It does not account for appliance efficiency: a 95%-efficient gas furnace delivers 95,000 BTU of heat per therm burned, while a heat pump can deliver two to four times more heat than the electrical energy it consumes.
With the default inputs, the btu is 3,412,141.6 BTU. Change any value above to recalculate instantly.
How to use the kwh to btu converter
- 1Enter the amount of energy from your bill or spec sheet.
- 2Choose the unit you are converting from.
- 3Read BTU as the main result, with kWh, therms and megajoules below.
- 4Factor in appliance efficiency separately when comparing fuels.
Formula and method
A kilowatt-hour is exactly 3.6 million joules (1,000 W for 3,600 s). The International Table BTU, used on US utility bills and equipment ratings, is 1,055.05585262 joules. Dividing gives about 3,412.14 BTU per kWh.
A therm is defined as 100,000 BTU, so one therm is about 29.3071 kWh. Megajoules are kWh × 3.6. All conversions here are energy-for-energy; to compare actual heating costs you also need each appliance's efficiency and your local prices.
- kWh
- Kilowatt-hours (3.6 MJ)
- BTU
- International Table British thermal unit (1,055.056 J)
- thm
- Therm (100,000 BTU)
Worked examples
Monthly electricity use of 1,000 kWh
1,000 × 3,600,000 J = 3.6 GJ; 3.6 GJ ÷ 1,055.056 J = 3,412,142 BTU, which equals about 34.12 therms.
Gas bill of 50 therms
50 therms = 5,000,000 BTU; 5,000,000 ÷ 3,412.14 = 1,465.36 kWh of energy.
12,000 BTU (one ton of cooling for an hour)
12,000 BTU ÷ 3,412.14 = 3.517 kWh. This is the heat a 1-ton air conditioner removes in one hour, not the electricity it uses.
Frequently asked questions
How many BTU are in a kWh?+
One kilowatt-hour equals about 3,412.14 BTU, using the International Table BTU of 1,055.056 joules.
How many kWh are in a therm?+
One therm is 100,000 BTU, which equals about 29.3071 kWh. Utilities sometimes round this to 29.3.
Is BTU per hour the same as BTU?+
No. BTU is energy; BTU per hour (BTU/h) is power. To convert BTU/h to watts, multiply by 0.29307. A heater rated at 10,000 BTU/h puts out about 2.93 kW of heat.
Is gas or electric heat cheaper per BTU?+
Divide each price by the energy it buys: $/kWh ÷ 3,412 gives $ per BTU of electricity, and $/therm ÷ 100,000 gives $ per BTU of gas. Then divide by appliance efficiency (or COP for heat pumps) to compare delivered heat.
Why do some sources list 3,413 BTU per kWh?+
Some references round 3,412.14 up, and others use the thermochemical BTU of 1,054.35 J, which gives about 3,414.4 BTU per kWh. The International Table BTU (3,412.14 per kWh) is the usual basis for US energy figures; the US EIA rounds it to 3,412.