Joules to kcal Converter
Convert joule to kilocalorie (food calorie) instantly. 1 J = 0.0002390057361 kcal, worked steps and a full reference table.
How to use it
- Type the value in joule — the result updates as you type.
- Use Swap to flip the direction, or change either dropdown to convert between any two units.
- Click the result to copy it. The URL updates too, so you can bookmark or share the exact conversion.
Examples
| 1 J | 0.0002390057361 kcal |
| 5 J | 0.001195028681 kcal |
| 10 J | 0.002390057361 kcal |
| 100 J | 0.02390057361 kcal |
One joule equals 0.00023900574 kilocalorie (food calorie)s (kcal). To convert joules to kilocalorie (food calorie)s, multiply by 0.00023900574; to go back the other way, multiply by 4184 instead.
The converter above does it as you type and shows the working underneath, so you can check the arithmetic rather than take the number on trust.
What joules and kilocalorie (food calorie)s actually measure
Joule (J) — The joule is the SI unit of energy — one watt for one second. Physics, mechanical work and food energy in most of the world.
Kilocalorie (food Calorie) (kcal) — A kilocalorie is a thousand small calories. Food labels call it a Calorie, capitalised. Nutrition and diet planning.
Joules to kcal conversion table
The most common values, worked out in advance. Anything not listed can be typed straight into the converter.
| J | kcal |
|---|---|
| 1 J | 0.00023900574 kcal |
| 2 J | 0.00047801147 kcal |
| 5 J | 0.0011950287 kcal |
| 10 J | 0.0023900574 kcal |
| 25 J | 0.0059751434 kcal |
| 50 J | 0.011950287 kcal |
| 100 J | 0.023900574 kcal |
How to convert joules to kilocalorie (food calorie)s by hand
Multiply the number of joules by 0.00023900574.
For example, 25 J × 0.00023900574 = 0.0059751434 kcal.
Going the other way, divide by 0.00023900574 — or multiply by 4184, which is the same thing and easier to do in your head.
Everything runs in your browser
There is no server involved in the calculation. The numbers you type never leave your device, nothing is logged, and the page keeps working with no connection once it has loaded. That is not a marketing line — it is simply how the tool is built, because a calculation like this has no reason to touch a network.
Questions people ask
How many kcal are in 1 J?
1 J equals exactly 0.0002390057361 kcal. Multiply any value in joule by 0.0002390057361 to get kilocalorie (food calorie).
Is anything uploaded to a server?
No. The whole calculation happens in your browser. Nothing is sent anywhere, and the page keeps working offline once loaded.
Last updated 18 August 2026