Joules to Calories Converter
Convert joules to calories instantly. Enter joules to get small calories or food Calories (kcal) by dividing by 4.184, with the reverse direction shown.
Updated 2026-06-14 · Free · No sign-up · Runs privately in your browser
Show the formula & steps
How the Joules to Calories Converter Works
This tool converts joules (J) to calories and back. The joule is the SI energy unit used in physics and on many food labels, while calories remain common in nutrition. You can pick the small calorie (cal) or the food Calorie (kcal), which differ by a factor of 1000.
The Formula
Small calories = joules ÷ 4.184 Food Calories (kcal) = joules ÷ 4,184
The thermochemical calorie is exactly 4.184 joules, so dividing joules by that factor gives small calories, and dividing by 4,184 gives kilocalories.
Worked Example
Convert 2,092 joules to small calories:
- cal = 2,092 ÷ 4.184 = 500 cal (which is 0.5 kcal)
A larger energy of 836,800 J:
- kcal = 836,800 ÷ 4,184 = 200 kcal
Going the other way, 300 small calories in joules:
- Joules = 300 × 4.184 = 1,255.2 J
Joules to Calories Quick Reference
| Joules | Small calories | Food Calories (kcal) |
|---|---|---|
| 100 | 23.9 | 0.0239 |
| 1,000 | 239.0 | 0.239 |
| 4,184 | 1,000 | 1 |
| 100,000 | 23,901 | 23.9 |
| 836,800 | 200,000 | 200 |
Reading Food Energy Labels
Many countries print food energy in kilojoules (kJ) alongside kilocalories (kcal). To turn a kJ figure into the familiar Calorie count, divide by 4.184 (since 1 kcal = 4.184 kJ). For example, an 837 kJ snack is about 200 Calories. This converter handles both the small calorie and the food Calorie so your result matches the label you are reading.
Frequently asked questions
How many calories are in a joule?+
One joule equals about 0.239 small calories, or about 0.000239 food Calories (kcal). To convert joules to small calories, divide by 4.184.
How do I convert joules to calories?+
Divide the joule value by 4.184 to get small calories, or by 4,184 to get food Calories. For example, 2,092 J ÷ 4.184 = 500 cal, which is also 0.5 kcal.
What is 1000 joules in calories?+
1,000 joules equals about 239 small calories, or about 0.239 food Calories (kcal). Dividing 1,000 by 4.184 gives 239.01.
How many calories is 1 kJ?+
1 kilojoule (1,000 J) equals about 239 small calories or about 0.239 food Calories. Many food labels show energy in both kJ and kcal for this reason.
Which calorie does this converter use?+
It uses the thermochemical calorie of exactly 4.184 joules. You can choose small calorie or food Calorie (kcal) so the output matches whichever unit you need.