Value, From, To
Waiting for input
How this calculator works
The joule is the SI unit of energy. Food labels use kilocalories (often written Calories) or kilojoules, electricity bills use kilowatt-hours, and heating and cooling equipment in the United States is rated in BTU. This converter uses the thermochemical calorie (4.184 J) and the International Table BTU.
Formula
- 1 kcal = 4,184 J = 4.184 kJ
- 1 kWh = 3,600,000 J = 3.6 MJ
- 1 BTU = 1,055.056 J
- 1 Wh = 3,600 J
Worked example
1 kwh to kj
- Value
- 1
- From
- Kilowatt-hour (kWh)
- To
- Kilojoule (kJ)
Result3,600 kJ
1 kWh = 3,600 kJ. 1 kWh = 3,600 kJ.
Frequently asked questions
How many calories are in a kilojoule?
1 kJ is about 0.239 kcal, and 1 kcal is 4.184 kJ. To turn a food label from kJ to Calories, divide by 4.184.
Is a food Calorie the same as a calorie?
No. The Calorie on food labels is a kilocalorie, equal to 1,000 small calories.
How many BTU are in a kilowatt-hour?
About 3,412 BTU. That is why a 1 kW heater is rated at roughly 3,412 BTU per hour.
Sources
More in Unit Converters
Results are estimates based on the values you enter and the published method shown above. They do not replace professional medical, financial or legal advice. Method reviewed October 7, 2026. About this site