Convert kilocalories to joules
Converting kilocalories to joules is a common energy task, whether you are checking a recipe, a spec sheet, a travel distance or a homework problem. Since 1 kcal equals 4,184 J, 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 kilocalories to joules
To convert kilocalories to joules, multiply the number of kilocalories by 4,184. For example, 10 kcal × 4,184 = 41,840 J.
J = kcal × 4,184
- Write down the value in kilocalories you want to convert.
- Multiply it by 4,184 (the exact kcal→J factor).
- The result is your value in joules. Check it below with the converter or the table.
Conversion table
Common values of kilocalories and their equivalents in joules:
| kcal | J |
|---|---|
| 1 | 4,184 |
| 2 | 8,368 |
| 3 | 12,552 |
| 4 | 16,736 |
| 5 | 20,920 |
| 10 | 41,840 |
| 20 | 83,680 |
| 25 | 104,600 |
| 50 | 209,200 |
| 100 | 418,400 |
| 250 | 1,046,000 |
| 500 | 2,092,000 |
About these units
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.
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.
Frequently asked questions
How do I convert kilocalories to joules?
To convert kilocalories to joules, multiply the number of kilocalories by 4,184. For example, 10 kcal × 4,184 = 41,840 J. Or skip the math: type the value into the converter at the top of this page and the result updates instantly.
How many joules are in 1 kilocalorie?
1 kcal = 4,184 J. That is the fixed relationship used by this converter and by international standards.
How many kilocalories are in 1 joule?
1 J = 0.000239006 kcal. If you are converting in the opposite direction, use our Joule to Kilocalorie converter for the dedicated table and FAQ.
Is the kilocalories to joules conversion exact?
Yes. Both units are defined by international agreement, so the factor of 4,184 is exact. Displayed results are rounded to 6 significant digits only for readability.
What is kilocalorie used for?
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.