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Convert Kilocalories to Kilojoules

1 kilocalorie (food calorie) = 4.184 kilojoules. Multiply the number of kilocalories by 4.184.

Result
4.184

1 kcal = 4.184 kJ

Multiply the number of kilocalories by 4.184.

Results are rounded for display. Double-check values for critical work.

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Kilocalories to Kilojoules table

KilocaloriesKilojoules
1 kcal4.184 kJ
2 kcal8.368 kJ
3 kcal12.552 kJ
4 kcal16.736 kJ
5 kcal20.92 kJ
10 kcal41.84 kJ
20 kcal83.68 kJ
25 kcal104.6 kJ
50 kcal209.2 kJ
100 kcal418.4 kJ
500 kcal2,092 kJ
1000 kcal4,184 kJ

Kilocalories to Kilojoules in your head

Multiply by 17, then divide by 4.

That lands within 2% of the exact value.

10 kcal → 42.5 kJ in your head, 41.84 kJ exactly.

About these units

The kilocalorie (food calorie) (kcal) is a specialist or regional unit of energy & work, equal to 4,184 joules.

The kilojoule (kJ) is a metric unit of energy & work, equal to 1,000 joules.

Going the other way, 1 kilojoule = 0.23900574 kilocalories. Diet calories, electricity bills in kilowatt-hours, boiler ratings in BTU and particle physics in electronvolts are all the same physical quantity. Convert energy across every scale from the atomic to the industrial.

Frequently asked

How many kilojoules are in a kilocalorie (food calorie)?
1 kilocalorie (food calorie) = 4.184 kilojoules.
How do you convert kilocalories to kilojoules?
Multiply the number of kilocalories by 4.184.
What is 10 kcal in kJ?
10 kcal = 41.84 kJ.

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