Kilocalories vs Kilojoules
Compare kilocalories and kilojoules side by side, convert in both directions, and see the exact factor - Energy units.
= 4.184 kJ
= 0.239006 kcal
1 kilocalorie = 4.184 kJ · 1 kilojoule = 0.239006 kcal
The Kilojoules is the smaller unit - the same amount has a bigger number when measured in it.
| Kilocalories (kcal) | Kilojoules (kJ) | Kilojoules (kJ) | Kilocalories (kcal) |
|---|---|---|---|
| 1 | 4.184 | 1 | 0.239006 |
| 2 | 8.368 | 2 | 0.478011 |
| 5 | 20.92 | 5 | 1.195 |
| 10 | 41.84 | 10 | 2.3901 |
| 25 | 104.6 | 25 | 5.9751 |
| 50 | 209.2 | 50 | 11.9503 |
| 100 | 418.4 | 100 | 23.9006 |
| 250 | 1,046 | 250 | 59.7514 |
| 500 | 2,092 | 500 | 119.5 |
| 1000 | 4,184 | 1000 | 239 |
Quick Answer
1 kilocalorie (kcal) = 4.184 kilojoules (kJ), and 1 kilojoule = 0.239006 kilocalories. Kilocalories is the larger unit, so the same physical amount needs a bigger number when measured in Kilojoules. Convert either way with the live tool below or the dedicated converter pages.
Key Facts
- 1 kilocalorie (kcal) = 4.184 kJ
- 1 kilojoule (kJ) = 0.239006 kcal
- Conversion is exact multiplication - no rounding in the factor
- Table below covers common values in both directions
- Dedicated converters: kcal→kJ and kJ→kcal pages with live tools
Frequently Asked Questions
Which is bigger, a kilocalorie or a kilojoule?
One kilocalorie equals 4.184 kJ, and one kilojoule equals 0.239006 kcal. The unit with the larger factor is the physically bigger one.
How do I convert kilocalories to kilojoules?
Multiply by the factor: value in kJ = value in kcal × 4.184. Example: 5 kcal = 20.92 kJ. Reverse: divide by 4.184 (or multiply by 0.239006).
Why are kilocalories and kilojoules different?
They come from different measurement systems - Kilocalories belongs to the metric (SI) world, Kilojoules to the US customary world (or another convention). The conversion is exact: 4.184 kJ per kilocalorie, no rounding needed for the factor itself.
Is there a quick way to convert without a calculator?
Memorize the 1-to factor: 1 kilocalorie ≈ 4.184 kJ. Then multiply. For 2 kcal that's ≈ 8.368 kJ.
Frequently Asked Questions
One kilocalorie equals 4.184 kJ, and one kilojoule equals 0.239006 kcal. The unit with the larger factor is the physically bigger one.
Multiply by the factor: value in kJ = value in kcal × 4.184. Example: 5 kcal = 20.92 kJ. Reverse: divide by 4.184 (or multiply by 0.239006).
They come from different measurement systems - Kilocalories belongs to the metric (SI) world, Kilojoules to the US customary world (or another convention). The conversion is exact: 4.184 kJ per kilocalorie, no rounding needed for the factor itself.
Memorize the 1-to factor: 1 kilocalorie ≈ 4.184 kJ. Then multiply. For 2 kcal that's ≈ 8.368 kJ.