Calories to Joules
One calorie equals 4.184 joules.
Joules = calories × 4.184
Energy Converter
Common Conversions
Energy Examples
Household Energy
- • Average home daily use: ~30 kWh
- • LED bulb (10W, 1 hour): 36 kJ
- • Microwave (1000W, 2 min): 120 kJ
- • Electric car (100 miles): ~30 kWh
Food Energy
- • Apple: ~350 kJ (80 kcal)
- • Slice of bread: ~315 kJ (75 kcal)
- • Can of soda: ~590 kJ (140 kcal)
- • Daily intake: ~8400 kJ (2000 kcal)
Energy Unit Reference
Scientific Units
- • Joule (J): SI base unit of energy
- • Calorie (cal): Energy to heat 1g water by 1°C
- • Electron Volt (eV): Atomic scale energy
- • Erg: CGS unit (very small)
Practical Units
- • kWh: Electrical energy billing
- • BTU: Heating/cooling systems
- • Therm: Natural gas billing
- • kcal: Food energy (Calories)
Calories to Joules Conversion Table
| cal | J |
|---|---|
| 1 | 4.184 |
| 2 | 8.368 |
| 5 | 20.92 |
| 10 | 41.84 |
| 25 | 104.6 |
| 50 | 209.2 |
| 100 | 418.4 |
| 250 | 1046 |
| 500 | 2092 |
| 1000 | 4184 |
| 2000 | 8368 |
| 2500 | 10460 |
| 5000 | 20920 |
| 10000 | 41840 |
About This Conversion
Calories to joules multiplies by 4.184, the defined value of the thermochemical calorie. The joule is the SI unit, so this is the step that brings a nutrition or heating figure into physics units.
Check which calorie you have first. The lowercase calorie here is the small one; the Calorie on a food label is a kilocalorie, a thousand times larger. A 250-calorie snack is 250 kcal, which is 1,046,000 joules, not the 1,046 joules this conversion gives.
Frequently Asked Questions
How many joules is one calorie?
One thermochemical calorie is exactly 4.184 joules.
How many joules is a food Calorie?
A food Calorie is a kilocalorie, so it is 4,184 joules.
Why are there two calories?
The small calorie heats one gram of water by 1 °C; the food Calorie heats one kilogram, so it is 1,000 times larger.
How many joules is 2000 calories?
2,000 small calories is 8,368 joules. 2,000 food Calories is 8,368,000 joules.
Worth Knowing
Calorie vs Kilocalorie
One food Calorie is one kilocalorie, equal to 1,000 small calories or 4,184 joules.
Related Conversions
Converting the other way? Joules to Calories
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