Quick answer: One kilowatt-hour is exactly 3.6 MJ, so 1 kWh = 3,412.1416 BTU and 1 kWh = 860.42065 kcal.
How it's calculated
The energy is changed to joules, the SI unit, then to your unit. 1 Wh is one watt for one hour (3,600 J), and 1 kWh, the unit on electricity bills, is 3.6 million joules.
Food labels use kilocalories (shown as Calories, kcal) and kilojoules: 1 kcal = 4.184 kJ. The BTU, used for air conditioners and gas, is the International Table value of 1,055.06 J.
To turn kWh into money, use the electricity cost calculator.
Worked examples
- One unit of electricity: 1 kWh = 3.6 MJ
- A 2,000 kcal daily diet: 2,000 kcal = 8,368 kJ
- A 2,000 kcal diet in kWh: 2,000 kcal = 2.3244444 kWh
Common energy conversions
| From | To |
|---|---|
| 1 kWh | 3.6 MJ |
| 1 kWh | 3,412.1416 BTU |
| 1 kcal | 4.184 kJ |
| 1 kJ | 0.23900574 kcal |
| 1 BTU | 1,055.0559 J |
| 1 BTU | 0.2521644 kcal |
| 1,000 kcal | 1.1622222 kWh |
| 1 thm | 29.300111 kWh |
| 1 cal | 4.184 J |
| 1 ft·lbf | 1.3558179 J |
Frequently asked questions
How many kcal are in a kJ?
1 kJ ≈ 0.239 kcal, and 1 kcal = 4.184 kJ.
Is a food Calorie the same as a calorie?
No. A food Calorie (capital C) is a kilocalorie, 1,000 small calories.
How many BTU in a kWh?
About 3,412.14 BTU.
How do I get kWh from watts?
Turn the watts into kilowatts and multiply by the hours. A 1,000 W heater left on for 3 hours uses 3 kWh. The electricity cost calculator will put a price on it.
What is a therm?
100,000 BTU, which is about 29.3 kWh. You'll mainly see it on gas bills in the US and the UK.
How many kcal are in 1 kWh?
About 860. A kWh is 3,600 kJ, and one kcal is 4.184 kJ.