1. How to convert kJ to kcal
The conversion is a single multiplication: kcal = kJ × 0.239005736138. Both units are defined
against the same base — the joule (J) — so the factor is fixed and the result
is exact to the precision shown.
Worked at the two values people ask for most: 1 kJ = 0.23900574 kcal and
100 kJ = 23.900574 kcal. Going the other way, kJ = kcal × 4.184, so
1 kcal = 4.184 kJ — a direction with its own page, kcal to kJ.
Results are given to eight significant figures. That is more precision than most jobs need — for a rough figure, treat 1 kJ as about 0.23900574 kcal and adjust — but rounding early and multiplying afterwards is how a small error becomes a visible one, so the full figure is what the converter carries.
2. Kilojoules to Kilocalories conversion table
| Kilojoules (kJ) | Kilocalories (food calories) (kcal) |
|---|---|
| 1 kJ | 0.23900574 kcal |
| 2 kJ | 0.47801147 kcal |
| 5 kJ | 1.1950287 kcal |
| 10 kJ | 2.3900574 kcal |
| 25 kJ | 5.9751434 kcal |
| 50 kJ | 11.950287 kcal |
| 100 kJ | 23.900574 kcal |
| 250 kJ | 59.751434 kcal |
| 500 kJ | 119.50287 kcal |
| 1,000 kJ | 239.00574 kcal |
Every row is the same factor applied — nothing in the table is a special case, and any value in between behaves the same way. Type your own figure into the converter above and the Formula tile shows the arithmetic being used, so the result is checkable rather than taken on trust.
3. What the two units are
- Kilojoules (kJ). One kJ is 1,000 J.
- Kilocalories (food calories) (kcal). One kcal is 4,184 J.
Both are converted through the joule (J): the value is multiplied by its own unit's factor to reach the base, then divided by the target unit's factor to leave it. No direct kJ to kcal factor has to exist or be kept correct, which is also why the converter can show the same value in all 10 energy units at once.
The calorie is two units: the food Calorie is a kilocalorie, and the physics calorie is a thousandth of it. This category uses kcal and kJ, the pair printed on nutrition labels, where 1 kcal is exactly 4.184 kJ by the thermochemical definition. A kilowatt-hour is exactly 3.6 MJ.
If the pair you actually want is not this one, the full unit converter runs every 10 energy units off the same factor table, along with 11 other categories of measurement.
4. Kilojoules to Kilocalories FAQs
How do I convert kJ to kcal?
Multiply by 0.239005736138. 1 kJ = 0.23900574 kcal, and 100 kJ = 23.900574 kcal. The factor is exact to the precision shown, so the only rounding is the one you choose to do at the end.
How many kcal is 1 kJ?
1 kJ = 0.23900574 kcal. The full formula is kcal = kJ × 0.239005736138, and 1 kcal = 4.184 kJ going the other way.
What is 100 kJ in kcal?
100 kJ = 23.900574 kcal. The table above works the same factor through 10 values, and the converter takes any figure you type — including decimals.
How do I convert kcal to kJ?
kJ = kcal × 4.184, so 1 kcal = 4.184 kJ. Use the Swap button in the converter to reverse the direction without retyping the value, or open the dedicated kcal to kJ page.
Which calorie does this use?
The kilocalorie — the food Calorie, exactly 4.184 kJ by the thermochemical definition. The physics calorie is a thousandth of it, and both appear in the converter. A kilowatt-hour is exactly 3.6 MJ.
Is anything I type sent to a server?
No. The factor table ships with the page and every conversion runs in your browser. Nothing is uploaded, logged or written to storage, and the converter keeps working offline once the page has loaded.