Calories to Joules
1 calorie = 4.184 joules (J)
Convert calories to joules instantly. 1 calorie = 4.184 joules. Free, accurate, with conversion table and formula.
Calorie (cal)
Joule (J)
| Unit | 1 cal equals |
|---|---|
| Joule (J) | 4.184 |
| Kilojoule (kJ) | 0.004184 |
| Calorie (cal) | 1 |
| Kilocalorie (kcal) | 0.001 |
| Watt Hour (Wh) | 0.00116222 |
| Kilowatt Hour (kWh) | 0.00000116222 |
| BTU (BTU) | 0.00396565 |
| Electron Volt (eV) | 2.61145e+19 |
| Foot-Pound (ft·lb) | 3.08596 |
How to convert calories to joules
- 1Take your value in calories (cal).
- 2Multiply by 4.184.
- 3The result is your value in joules (J).
Calories to Joules conversion table
| Calories (cal) | Joules (J) |
|---|---|
| 1 | 4.184 |
| 2 | 8.368 |
| 5 | 20.92 |
| 10 | 41.84 |
| 25 | 104.6 |
| 50 | 209.2 |
| 100 | 418.4 |
| 250 | 1,046 |
| 500 | 2,092 |
| 1,000 | 4,184 |
Frequently asked
How many joules are in a calorie?
1 calorie equals 4.184 joules (J).
How do I convert calories to joules?
Multiply the number of calories by 4.184 to get joules.
What is 10 calories in joules?
10 cal equals 41.84 J.
What is 100 calories in joules?
100 cal equals 418.4 J.
How do I convert joules back to calories?
Multiply joules by 0.239006 (the reciprocal) or use the swap button above.
Where you'll actually use this
Energy converters bridge joules, calories, kilowatt-hours, BTUs, and electron-volts — the same physical quantity expressed for science, nutrition, electricity, or HVAC.
- Electricity bills
Usage is billed in kWh. Convert to joules for physics, or to BTU for HVAC comparisons.
- Nutrition
Food 'calories' are actually kilocalories (kcal). 1 kcal = 4,184 J. EU labels list both kcal and kJ.
- HVAC & cooling
Air conditioner output is quoted in BTU/h in the US, watts elsewhere.
Common mistakes to avoid
- Calories vs kilocalories
When a food label says '250 calories' it really means 250 kcal = 250,000 small calories.
- kW vs kWh
kW is power (rate); kWh is energy (total). A 1 kW heater running for 2 hours uses 2 kWh.
Did you know?
A typical modern fridge uses about 1 kWh per 24 hours — roughly $0.10–$0.30 depending on local rates.
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