Convert kilocalories to kilojoules
Converting kilocalories to kilojoules 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 kJ, 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 kilojoules
To convert kilocalories to kilojoules, multiply the number of kilocalories by 4.184. For example, 10 kcal × 4.184 = 41.84 kJ.
kJ = kcal × 4.184
- Write down the value in kilocalories you want to convert.
- Multiply it by 4.184 (the exact kcal→kJ factor).
- The result is your value in kilojoules. Check it below with the converter or the table.
Conversion table
Common values of kilocalories and their equivalents in kilojoules:
| kcal | kJ |
|---|---|
| 1 | 4.184 |
| 2 | 8.368 |
| 3 | 12.552 |
| 4 | 16.736 |
| 5 | 20.92 |
| 10 | 41.84 |
| 20 | 83.68 |
| 25 | 104.6 |
| 50 | 209.2 |
| 100 | 418.4 |
| 250 | 1,046 |
| 500 | 2,092 |
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.
Kilojoule (kJ). A kilojoule is 1,000 joules, the practical unit for food energy in Australia and Europe and for mechanical work. One kilocalorie equals 4.184 kilojoules.
Frequently asked questions
How do I convert kilocalories to kilojoules?
To convert kilocalories to kilojoules, multiply the number of kilocalories by 4.184. For example, 10 kcal × 4.184 = 41.84 kJ. Or skip the math: type the value into the converter at the top of this page and the result updates instantly.
How many kilojoules are in 1 kilocalorie?
1 kcal = 4.184 kJ. That is the fixed relationship used by this converter and by international standards.
How many kilocalories are in 1 kilojoule?
1 kJ = 0.239006 kcal. If you are converting in the opposite direction, use our Kilojoule to Kilocalorie converter for the dedicated table and FAQ.
Is the kilocalories to kilojoules 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.