Kilocalories to Kilojoules
A kilocalorie, the "Calorie" on food labels, is the energy needed to raise 1 kilogram of water by 1°C. A kilojoule is 1,000 joules, used on nutrition labels outside the US to state food energy content. 1 kcal equals 4.184 kJ, so converting between them is a matter of multiplying by that fixed factor — type any value into the converter below and both sides update instantly as you type.
Both units belong to energy, measured here against energy's base unit (J) — every other energy unit on this site converts through that same reference point, which is why the table below can also be read as a quick cross-check against nearby values.
Formula
kJ = kcal × 4.184
kcal = kJ × ≈0.239006
Worked example: 5 kcal × 4.184 = 20.92 kJ.
Conversion table
| Kilocalorie (kcal) | Kilojoule (kJ) |
|---|---|
| 1 kcal | 4.184 kJ |
| 2 kcal | 8.368 kJ |
| 3 kcal | 12.552 kJ |
| 5 kcal | 20.92 kJ |
| 10 kcal | 41.84 kJ |
| 20 kcal | 83.68 kJ |
| 25 kcal | 104.6 kJ |
| 50 kcal | 209.2 kJ |
| 100 kcal | 418.4 kJ |
| 250 kcal | 1,046 kJ |
| 500 kcal | 2,092 kJ |
| 1,000 kcal | 4,184 kJ |
Frequently asked
- How many Kilojoules in a kilocalorie?
- 1 kcal equals 4.184 kJ.
- How do I convert Kilocalories to Kilojoules?
- Multiply the value in kcal by 4.184 to get kJ. The converter above does this instantly as you type.
- Is the conversion exact?
- Yes — Kilocalorie and Kilojoule are both defined by a fixed conversion factor to energy's base unit (J), so the result shown is exact to the precision displayed, not an approximation.