Convert kilojoules to kilocalories
Kilojoule (kJ) to kilocalorie (kcal). One kilojoule equals 0.239006 kilocalories.
Formula
Kilojoule to kilocalorie conversion table
| Kilojoules | Kilocalories | Kilocalories | Kilojoules |
|---|---|---|---|
| 1 kJ | 0.239006 kcal | 1 kcal | 4.184 kJ |
| 2 kJ | 0.478011 kcal | 2 kcal | 8.368 kJ |
| 3 kJ | 0.717017 kcal | 3 kcal | 12.552 kJ |
| 5 kJ | 1.195 kcal | 5 kcal | 20.92 kJ |
| 10 kJ | 2.3901 kcal | 10 kcal | 41.84 kJ |
| 20 kJ | 4.7801 kcal | 20 kcal | 83.68 kJ |
| 50 kJ | 11.9503 kcal | 50 kcal | 209.2 kJ |
| 100 kJ | 23.9006 kcal | 100 kcal | 418.4 kJ |
| 500 kJ | 119.5 kcal | 500 kcal | 2092 kJ |
| 1000 kJ | 239.01 kcal | 1000 kcal | 4184 kJ |
To convert kilojoules to kilocalories, divide the number of kilojoules by 4.184. One kilojoule equals 0.239006 kilocalories, and one kilocalorie equals 4.184 kilojoules, so the relationship is fixed and exact. As a worked example, 10 kJ comes to 2.3901 kcal. Enter your own figure in the converter above to get an instant answer, or use the swap button to flip the direction. This is a energy conversion, and like every tool on UnitGlide it runs locally in your browser with no account or upload required. The table further down shows a range of common kilojoule values already worked out in kilocalories, plus the reverse kilocalorie to kilojoule direction, which is handy for quick reference or double-checking a result by hand.
Kilojoule to kilocalorie in practice
Kilojoules to kilocalories is the conversion European food labels force on anyone who thinks in Calories, because the EU lists energy in kilojoules first.
Reading a European label
EU nutrition labels give energy in kilojoules and kilocalories side by side, but much of the world only counts kcal, so a snack listed as 837 kJ is the 200 kcal a dieter is watching. Fitness apps that import kJ from a barcode need the same step to show a familiar Calorie figure, and a 2,000 kcal daily target is 8,368 kJ the other way round.
The factor is 4.184, not 1,000
This is where people slip: kilojoules and kilocalories are not a metric power of ten apart. One kilocalorie is 4.184 kilojoules, so you divide kJ by 4.184, not by 1,000. A 500 kJ yoghurt is about 120 kcal. Treating the pair like grams and kilograms, or like the clean kcal-to-cal step, is the classic mistake and throws the answer out by more than fourfold.
Rounding on labels
Labels already round both numbers independently, so a small mismatch between a converted value and the printed kcal is normal and not an error on anyone's part. For a quick head estimate, dividing kJ by four slightly overstates the kcal; using 4.2 lands you within about a percent of the true figure.
Energy in, not power
The kilojoule here is an amount of energy in a food, not a rate, so it converts straight to kilocalories. It is a different quantity from the kilowatts on an appliance or the kilojoules-per-second that make up a watt, and keeping food energy separate from power ratings avoids mixing two unrelated conversions.
Portion sums
Because labels state energy per 100 grams as well as per portion, this conversion often runs twice: first to turn the per-100-gram kJ into kcal, then to scale it to the amount actually eaten. A cereal at 1,500 kJ per 100 g is 359 kcal per 100 g, so a 40 g bowl is about 144 kcal, the kind of chain a calorie-counter runs off an EU packet all day.
Frequently asked questions
How many kilocalories are in a kilojoule?
One kilojoule equals 0.239006 kilocalories. The ratio is constant, so you can multiply any number of kilojoules by 0.239006 to get kilocalories.
What is the formula to convert kilojoules to kilocalories?
Use kilocalories = kilojoules ÷ 4.184. UnitGlide applies this exact formula for every value, so results stay accurate across the whole range.
How do I convert kilocalories back to kilojoules?
Go the other way by using one kilocalorie equals 4.184 kilojoules. You can also press the swap button in the converter above to flip the direction in one click.
Is this kilojoule to kilocalorie converter accurate?
Yes. It uses internationally defined SI conversion factors, as maintained by the BIPM, and all math runs in your browser so nothing is rounded away on a server. For everyday use the displayed precision is more than enough.