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Kilojoules to Kilocalories

One kilojoule equals 0.239006 kilocalories.

Kilocalories = kilojoules ÷ 4.184

Energy Converter

Common Conversions

Energy Examples

Household Energy

  • • Average home daily use: ~30 kWh
  • • LED bulb (10W, 1 hour): 36 kJ
  • • Microwave (1000W, 2 min): 120 kJ
  • • Electric car (100 miles): ~30 kWh

Food Energy

  • • Apple: ~350 kJ (80 kcal)
  • • Slice of bread: ~315 kJ (75 kcal)
  • • Can of soda: ~590 kJ (140 kcal)
  • • Daily intake: ~8400 kJ (2000 kcal)

Energy Unit Reference

Scientific Units

  • Joule (J): SI base unit of energy
  • Calorie (cal): Energy to heat 1g water by 1°C
  • Electron Volt (eV): Atomic scale energy
  • Erg: CGS unit (very small)

Practical Units

  • kWh: Electrical energy billing
  • BTU: Heating/cooling systems
  • Therm: Natural gas billing
  • kcal: Food energy (Calories)

Kilojoules to Kilocalories Conversion Table

kJkcal
10023.9006
20047.8011
30071.7017
40095.6023
500119.5029
750179.2543
1000239.0057
1500358.5086
2000478.0115
4000956.0229
60001434.0344
80001912.0459
87002079.3499
100002390.0574

About This Conversion

Kilojoules to kilocalories divides by 4.184, the conversion needed to read a European or Australian food label in the Calorie figures used in the US and UK.

A rough mental version is to divide by four and take off a little, which is accurate to about 4 percent: 500 kJ estimated as 125 kcal is really 119.5. For counting over a day the exact divisor is worth using, since the error compounds across every entry.

Frequently Asked Questions

How many Calories is 1000 kJ?

1,000 kJ is about 239 kcal.

How many Calories is 8700 kJ?

8,700 kJ is about 2,079 kcal.

What is the quick way to convert kJ to Calories?

Divide by 4.184. Dividing by 4 gets you within about 4 percent.

Why do labels show both?

Kilojoules are the SI unit and required in many countries; kilocalories are what most consumers recognise.

Worth Knowing

Calorie vs Kilocalorie

One food Calorie is one kilocalorie, equal to 1,000 small calories or 4,184 joules.