Joules to Calories Converter
Convert joules (J) to calories (cal) instantly. Type a value — the result updates as you type, and the swap button converts the other way.
Joules to Calories formula
cal = J ÷ 4.184
1 joule = 0.239 calories · 1 calorie = 4.18 joules
To convert joules to calories, divide the value by 4.184. For example, 1000 J:
cal = 1000 ÷ 4.184cal = 239.005736
So 1000 J = 239.01 cal.
Mental math shortcut
Quick mental estimate: multiply by 0.24. For 1000 J that gives about 240 cal — within 1% of the exact answer. Use the exact formula when precision matters.
Joules to Calories conversion table
Calories back to Joules
The same values converted the other way, rounded for everyday use:
| Calories | Joules |
|---|---|
| 0.239 cal | 1 J |
| 2.39 cal | 10 J |
| 23.9 cal | 100 J |
| 100 cal | 418.4 J |
| 239.01 cal | 1000.02 J |
| 1000 cal | 4184 J |
| 2390.06 cal | 10000.01 J |
About the units
Joules (J)
The joule is the SI unit of energy. One food Calorie (kcal) equals 4,184 joules.
Calories (cal)
The small (thermochemical) calorie is exactly 4.184 joules — the energy to warm 1 gram of water by about 1 °C.
Frequently asked questions
How many calories are in a joule?
One joule equals 0.239 calories.
What is 1000 Joules in Calories?
1000 J = 239.01 cal.
How do I convert Calories back to Joules?
Multiply the calories by 4.184. Or use the Calories to Joules converter.