Energy converter
Joules, calories, kilowatt-hours and more.
Runs in your browserNo sign-upNo watermark
Quick answer
To convert energy units, type a number, choose the unit you have and the unit you want. The answer updates as you type.
1 kcal = 4.184 kJ
1 kcal in every energy unit
| Joule | 4184 J |
|---|---|
| Kilojoule | 4.184 kJ |
| Calorie (small) | 1000 cal |
| Kilocalorie (food Calorie) | 1 kcal |
| Watt-hour | 1.162222222 Wh |
| Kilowatt-hour | 0.001162222222 kWh |
| British thermal unit | 3.965666831 BTU |
How to use the energy tool
- Type the number you want to convert.
- Choose the unit you have in "From" and the one you want in "To".
- Read the answer. The ⇄ button swaps the two units, and the table shows every unit at once.
This energy converter uses exact conversion factors and shows the result with up to 10 significant digits.
Common questions
What is the difference between a calorie and a kilocalorie?
A food Calorie (written with a capital C) is a kilocalorie, which is 1,000 small calories. The kcal row is the one on food labels.
How many kilojoules are in a kilocalorie?
One kilocalorie is 4.184 kilojoules.
How accurate is it?
It uses the exact defined conversion factors and shows up to 10 significant digits, so rounding noise is hidden but real precision is kept.
Does it work offline?
Once the page has loaded, yes: it calculates in your browser and sends nothing anywhere.