Calories to Kilojoules
Convert calories to kilojoules instantly. 1 cal = 0.004184 kJ. Includes the exact factor, a conversion table of common values and the definition of both units.
How to convert calories to kilojoules
To convert calories to kilojoules, divide by 239.0057361377 (multiply by 0.004184). The relationship is fixed, so the same factor works for any quantity — there is nothing to look up and nothing that changes with temperature, location or context.
kJ = cal × 0.004184
Calories to Kilojoules conversion table
The values people look up most often, rounded for reading. Use the calculator above for anything in between.
| Calories | Kilojoules |
|---|---|
| 1 cal | 0.004184 kJ |
| 2 cal | 0.008368 kJ |
| 3 cal | 0.012552 kJ |
| 5 cal | 0.02092 kJ |
| 10 cal | 0.04184 kJ |
| 20 cal | 0.08368 kJ |
| 25 cal | 0.1046 kJ |
| 50 cal | 0.2092 kJ |
| 100 cal | 0.4184 kJ |
| 500 cal | 2.092 kJ |
| 1,000 cal | 4.184 kJ |
What is a calory?
The small calorie: energy to raise one gram of water by one degree.
What is a kilojoule?
A thousand joules. Food energy is labelled in kilojoules outside the US.
The formula
kJ = cal × 0.004184
Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.
How to use the Calories to Kilojoules
- Type the number of calories you want to convert.
- Read the result in kilojoules straight away — there is no button to press.
- Check the table below for the values that come up most often, or reverse the conversion with the linked kilojoules to calories page.
Calories to Kilojoules — frequently asked questions
How many kilojoules are in a calory?
One calory equals 0.004184 kJ. kJ = cal × 0.004184
What is the formula to convert calories to kilojoules?
The formula is kJ = cal × 0.004184. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.
How do I convert kilojoules back to calories?
Divide instead of multiplying: one kilojoule is 239.0057361377 cal. The reverse converter is linked in the related tools list.
Is this conversion exact?
Yes. Both units are defined against the same base unit by international agreement, so the factor is exact — any rounding you see is only in the display, which you can widen by entering more decimal places.
Is this calories to kilojoules free to use?
Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.
What people search for
This page answers each of these searches. They are the exact phrases visitors use to find the calories to kilojoules.
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- how many kilojoules in a calory
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About this calculator
Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.
Last reviewed August 19, 2026 · Calculation runs client-side · No data collected · Report an error