How to Convert Calories to Kilojoules
Calories (cal) and kilojoules (kJ) both measure energy. In nutrition, what we call a "calorie" is technically a kilocalorie (kcal)βthe energy needed to raise 1 kg of water by 1Β°C. Food labels in Australia, New Zealand, and Europe typically use kilojoules, while the US uses kilocalories (Calories with a capital C).
The conversion factor is 1 kcal (food Calorie) = 4.184 kJ.
The Conversion Formula
Kilojoules = Calories (kcal) Γ 4.184
Going the other direction:
Calories = Kilojoules Γ· 4.184
Step-by-Step Example
A snack has 250 Calories (kcal). What is that in kilojoules?
- 250 Γ 4.184 = 1,046 kJ
Reference Table
| Calories (kcal) | Kilojoules (kJ) |
|---|---|
| 100 kcal | 418 kJ |
| 200 kcal | 837 kJ |
| 500 kcal | 2,092 kJ |
| 1,000 kcal | 4,184 kJ |
| 2,000 kcal | 8,368 kJ |
| 2,500 kcal | 10,460 kJ |
Daily Energy Needs
The average adult requires approximately 2,000β2,500 kcal (8,368β10,460 kJ) per day, depending on age, sex, and activity level. Australian and New Zealand food labels use kJ, with the recommended daily intake often listed as 8,700 kJ (2,080 kcal).
Use our calories-to-kilojoules calculator to convert any energy value instantly.