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Convert Kilojoules to Kilocalories

1 kilojoule is 0.239006 kcal. One kilojoule is exactly 0.239005736138 kilocalories.

One kilojoule is 0.23900574 kilocalories. To convert kilojoules to kilocalories, multiply by 0.23900574; to go the other way, divide by 0.23900574 or multiply by 4.184. The factor is exact rather than rounded: it follows from NIST Special Publication 811. A thousand joules.

Factor checked against the defining standard · How we check

Kilocalories
0.239006 kcal
Kilojoules × 0.23900574
value * 0.2390057361380.239 kcal

1 kilojoule in every energy unit

UnitValueExact factor
joules1,000 J× 1,000
kilojoules (as entered)1 kJ
calories239.0057361 cal× 239.005736138
kilocalories0.2390057361 kcal× 0.239005736138
watt-hours0.2777777778 Wh× 0.277777777778
kilowatt-hours0.0002777777778 kWh× 0.000277777777778
British thermal units0.9478171203 BTU× 0.947817120313
foot-pounds737.5621493 ft·lbf× 737.562149277

Factors are entered by hand from NIST Special Publication 811 rather than derived from a units library, so the ones that terminate are exact rather than rounded.

How do you convert kilojoules to kilocalories?

  1. 1.Take the measurement in kilojoules.
  2. 2.Multiply by 0.23900574 — that is how many kilocalories fit in one kilojoule.
  3. 3.To go back the other way, divide by 0.23900574, or multiply by 4.184.

Worked example: 25 kilojoules to kilocalories

Formula
kJ × 0.23900574 = kcal
Arithmetic
25 × 0.23900574 = 5.975143 kcal
Answer
25 kJ = 5.975143 kcal

The factor is rounded for display; the figure above is computed from the full value.

Kilojoules to kilocalories conversion table

KilojoulesKilocalories
1 kJ0.239006 kcal
2 kJ0.478011 kcal
3 kJ0.717017 kcal
4 kJ0.956023 kcal
5 kJ1.195029 kcal
6 kJ1.434034 kcal
7 kJ1.67304 kcal
8 kJ1.912046 kcal
9 kJ2.151052 kcal
10 kJ2.390057 kcal
12 kJ2.868069 kcal
15 kJ3.585086 kcal
20 kJ4.780115 kcal
25 kJ5.975143 kcal
50 kJ11.950287 kcal
100 kJ23.900574 kcal
200 kJ47.801147 kcal
300 kJ71.701721 kcal
500 kJ119.502868 kcal
1000 kJ239.005736 kcal
2000 kJ478.011472 kcal
5000 kJ1,195.028681 kcal
10000 kJ2,390.057361 kcal

What is a kilojoule?

A thousand joules. Food energy outside the US is labelled here, alongside or instead of calories.

What is a kilocalorie?

A thousand small calories, and what a food label means by "Calories" with a capital C. A 2,000 calorie diet is 2,000 kcal, or 8.4 megajoules.

How many kilocalories are in a kilojoule?

One kilojoule is 0.23900574 kilocalories. Going the other way, one kilocalorie is 4.184 kilojoules. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.

Every energy unit here

UnitSymbolOne of these is
JoulesJthe base unit
KilojouleskJ1000 joule
Caloriescal4.184 joule
Kilocalorieskcal4184 joule
Watt-hoursWh3600 joule
Kilowatt-hourskWh3600000 joule
British thermal unitsBTU1055.0559 joule
Foot-poundsft·lbf1.3558179 joule

Source: NIST Special Publication 811 — the thermochemical calorie is exactly 4.184 J

Questions people actually ask

How many kilocalories are in a kilojoule?
0.23900574. A thousand small calories, and what a food label means by "Calories" with a capital C. A 2,000 calorie diet is 2,000 kcal, or 8.4 megajoules.
How do I convert kilocalories back to kilojoules?
Divide by 0.23900574, or multiply by 4.184 — they are the same operation.

Other energy conversions

Kilocalories to kilojoules — the same conversion the other way.

Calculators that work in energy