Log in Sign up free

Energy Converter (J, kWh, kcal, BTU)

Convert energy between joules, kilojoules, calories, kilocalories, watt-hours, kWh, BTU, electronvolts and therms.

Runs instantly in your browser — results update as you type.

How many joules are in a kilowatt-hour?

One kilowatt-hour equals 3,600,000 joules (3.6 MJ). One food Calorie (kcal) is 4,184 joules, and one BTU is about 1,055 joules.

Common conversions

FromTo
1 kWh3,600 kJ = 3,412 BTU = 860 kcal
1 kcal (food Calorie)4.184 kJ
1 BTU1.055 kJ
1 therm (US)29.3 kWh

Use it for electricity bills (kWh), nutrition labels (kcal and kJ), heating and air-conditioning (BTU, therms) and physics (joules, electronvolts).

Frequently asked questions

Is a food Calorie the same as a calorie?

No: a food Calorie (capital C) is a kilocalorie, 1,000 small calories.

How many kWh is 1,000 BTU?

About 0.293 kWh.

What is the difference between kW and kWh?

kW is power (a rate); kWh is energy (power × time). Convert power with the Power Converter.