Convert joules to kilocalories
Converting joules to kilocalories is a common energy task, whether you are checking a recipe, a spec sheet, a travel distance or a homework problem. Since 1 J equals 0.000239006 kcal, the math is a single multiplication — and this page does it for you instantly, with the formula, a table of common values and answers to the questions people ask most.
Exact factor
How to convert joules to kilocalories
To convert joules to kilocalories, multiply the number of joules by 0.000239006. For example, 10 J × 0.000239006 = 0.00239006 kcal.
kcal = J × 0.000239006
- Write down the value in joules you want to convert.
- Multiply it by 0.000239006 (the exact J→kcal factor).
- The result is your value in kilocalories. Check it below with the converter or the table.
Conversion table
Common values of joules and their equivalents in kilocalories:
| J | kcal |
|---|---|
| 1 | 0.000239006 |
| 2 | 0.000478011 |
| 3 | 0.000717017 |
| 4 | 0.000956023 |
| 5 | 0.00119503 |
| 10 | 0.00239006 |
| 20 | 0.00478011 |
| 25 | 0.00597514 |
| 50 | 0.0119503 |
| 100 | 0.0239006 |
| 250 | 0.0597514 |
| 500 | 0.119503 |
About these units
Joule (J). The joule is the SI unit of energy: the work done by one newton acting over one meter. Food labels in most countries, physics and engineering use joules.
Kilocalorie (kcal). A kilocalorie equals 1,000 small calories and is the 'Calorie' seen on food labels. An adult needs roughly 2,000–2,500 kcal per day, depending on activity.
Frequently asked questions
How do I convert joules to kilocalories?
To convert joules to kilocalories, multiply the number of joules by 0.000239006. For example, 10 J × 0.000239006 = 0.00239006 kcal. Or skip the math: type the value into the converter at the top of this page and the result updates instantly.
How many kilocalories are in 1 joule?
1 J = 0.000239006 kcal. That is the fixed relationship used by this converter and by international standards.
How many joules are in 1 kilocalorie?
1 kcal = 4,184 J. If you are converting in the opposite direction, use our Kilocalorie to Joule converter for the dedicated table and FAQ.
Is the joules to kilocalories conversion exact?
Yes. Both units are defined by international agreement, so the factor of 0.000239006 is exact. Displayed results are rounded to 6 significant digits only for readability.
What is joule used for?
The joule is the SI unit of energy: the work done by one newton acting over one meter. Food labels in most countries, physics and engineering use joules.