Convert Kilojoule to Calorie (kJ → cal)
The kilojoule is the standard unit on European nutrition labels and in mid-scale chemical and physical calculations.
Kilojoule to Calorie Conversion Table
10 common values| Kilojoule | Calorie |
|---|---|
| 1 kJ | 239.00574 cal |
| 10 kJ | 2,390.0574 cal |
| 100 kJ | 23,900.574 cal |
| 500 kJ | 119,502.87 cal |
| 1,000 kJ | 239,005.74 cal |
| 5,000 kJ | 1,195,028.7 cal |
| 10,000 kJ | 2,390,057.4 cal |
| 50,000 kJ | 11,950,287 cal |
| 100,000 kJ | 23,900,574 cal |
| 500,000 kJ | 119,502,870 cal |
How to Convert Kilojoule to Calorie Manually
Step by StepConverting kilojoules to calories is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.
- 1Take your value in kilojoulesStart with the number of kilojoules (kJ) you want to convert.
- 2Multiply by 239.00574The conversion factor from kJ to cal is 239.00574. Multiply your value by this number.
- 3Read the result in caloriesThe result is your value in calories (cal).
Formula
Multiply the value in kilojoules by 239.00574. For the reverse direction, multiply by 0.004184.
cal = kJ × 239.00574kJ = cal × 0.004184Tips
Use these in everyday conversions- 1 kJ = 1000 J = 0.239 kcal.
- EU nutrition labels must show both kJ and kcal.
- For quick conversion: kcal × 4.2 = kJ.
Common Mistakes
Avoid these- Assuming European labels use kcal only — they use both kJ and kcal.
- Confusing kJ with kW (power).
- Using kcal when kJ is requested in scientific context.
About Kilojoule and Calorie
What is the Kilojoule?
The kilojoule equals 1,000 joules and is the standard unit on European nutrition labels and in mid-scale chemical and physical calculations. EU regulations require food packaging to display energy in kilojoules (typically with kilocalories also shown for consumer familiarity): a chocolate bar might show '2,100 kJ / 500 kcal' per 100 g. The kilojoule is also common in chemistry (bond energies), electrical engineering (capacitor storage), and small-mechanical-energy contexts. A car battery typically stores about 1,800 kJ; lifting a person 1 meter requires roughly 0.7 kJ. The kilojoule relates to the joule (1,000 J = 1 kJ), the kilocalorie (1 kcal = 4.184 kJ), the watt-hour (1 kWh = 3,600 kJ), and the megajoule (1,000 kJ = 1 MJ). The conversion factor 4.184 (kJ per kcal) is one of the most-used numbers in nutrition labeling.
- EU and UK nutrition labels
- Mechanical work in engineering
- Battery capacity in vehicles
100 g chocolate: ~2100 kJ. EU daily intake (adult): ~8400 kJ. Tesla Model 3 battery: ~270 MJ = 270,000 kJ.
What is the Calorie?
The calorie equals exactly 4.184 joules (the 'thermochemical calorie') and is the historical unit for heat in chemistry and physics. It was originally defined as the heat needed to raise 1 gram of water by 1°C (a definition that varied slightly with starting temperature, hence multiple 'calories' — 4.184 J was set as the exact thermochemical convention). The calorie is widely used in older physics and chemistry literature for reaction energies, specific heat capacities, and thermodynamic calculations. Note: this 'small calorie' (lowercase c) is 1/1000 of the food Calorie (capital C) used in nutrition. The chemistry calorie relates to the joule (4.184 J = 1 cal), the kilocalorie (1,000 cal = 1 kcal = 1 food Calorie), and the BTU (1 BTU ≈ 252 cal). Modern SI usage in scientific publications has largely replaced the calorie with the joule, but it persists in medical and chemistry contexts.
- Thermodynamics and older physics texts
- Chemistry energy calculations
- Some engineering heat-transfer contexts
Raising 1 g of water 1 °C: 1 cal. A 100 kcal snack = 100,000 small calories.