1 kWh =
3,600 kJ
What the Energy Converter does
This tool converts between energy units used in nutrition, electricity bills, heating, and physics. It handles joules and kilojoules, calories and kilocalories, watt-hours and kilowatt-hours, BTU, and foot-pounds. That makes it useful for reading a food label in kcal versus kJ, comparing an appliance rating in kWh, or sizing heating quoted in BTU.
How to use it
- Enter the amount in the Value box.
- Choose your starting unit under From (for example kWh).
- Choose the unit you want under To (for example kJ).
- Press Convert to see the result below.
Calories and kilocalories
A common source of confusion is the calorie. The Calorie listed on food packaging is a kilocalorie (1 kcal = 1000 small calories = 4184 joules), so pick kcal when you work with nutrition figures. The converter uses standard factors and runs entirely in your browser, so your numbers are never uploaded.
Frequently asked questions
- Which energy units are included?
- Joule, kilojoule, calorie, kilocalorie (kcal), watt-hour, kilowatt-hour (kWh), BTU, and foot-pound. Any pair works, such as kWh to kJ or kcal to kJ.
- Is a food calorie the same as a calorie here?
- A food Calorie on nutrition labels is actually a kilocalorie (kcal). So for food energy, use the kcal unit. The plain calorie unit here is the smaller scientific calorie.
- Does it upload my data?
- No. Everything runs in your browser, so nothing you type is sent or saved. No sign-up, no limits.
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Last updated: June 17, 2026