Calories to Joules
Convert calories to joules instantly. 1 cal = 4.184 J. Includes the exact factor, a conversion table of common values and the definition of both units.
How to convert calories to joules
To convert calories to joules, multiply by 4.184. 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.
J = cal × 4.184
Calories to Joules conversion table
The values people look up most often, rounded for reading. Use the calculator above for anything in between.
| Calories | Joules |
|---|---|
| 1 cal | 4.184 J |
| 2 cal | 8.368 J |
| 3 cal | 12.552 J |
| 5 cal | 20.92 J |
| 10 cal | 41.84 J |
| 20 cal | 83.68 J |
| 25 cal | 104.6 J |
| 50 cal | 209.2 J |
| 100 cal | 418.4 J |
| 500 cal | 2,092 J |
| 1,000 cal | 4,184 J |
What is a calory?
The small calorie: energy to raise one gram of water by one degree.
What is a joule?
The SI unit of energy: one newton-metre, or one watt for one second.
The formula
J = cal × 4.184
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 Joules
- Type the number of calories you want to convert.
- Read the result in joules 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 joules to calories page.
Calories to Joules — frequently asked questions
How many joules are in a calory?
One calory equals 4.184 J. J = cal × 4.184
What is the formula to convert calories to joules?
The formula is J = cal × 4.184. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.
How do I convert joules back to calories?
Divide instead of multiplying: one joule is 0.2390057361 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 joules 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 joules.
- calories to joules
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- how many joules 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