Kilojoules to Calories Converter
Convert kilojoules to food Calories — divide by 4.184. Results update as you type; exact factors shown.
One kilojoule is 0.239 kilocalorie (food Calorie) — see the exact factor, not a rounded rule of thumb.
How the kilojoules to calories converter works
Energy converts through the joule. A thermochemical calorie is exactly 4.184 J, so a food Calorie (kcal) is 4.184 kJ. A kilowatt-hour is exactly 3.6 MJ. A BTU is 1,055.056 J and a US therm is 100,000 BTU.
The UK is metric for most trade and science but keeps miles, pints, stone and mpg (with the imperial gallon) in daily life.
Common energy conversions
| From | To | Units |
|---|---|---|
| 100 kJ | 23.9006 kcal | kilojoules to kilocalorie (food Calorie) |
| 500 kJ | 119.5029 kcal | kilojoules to kilocalorie (food Calorie) |
| 1,000 kJ | 239.0057 kcal | kilojoules to kilocalorie (food Calorie) |
| 2,000 kJ | 478.0115 kcal | kilojoules to kilocalorie (food Calorie) |
| 4,184 kJ | 1,000 kcal | kilojoules to kilocalorie (food Calorie) |
| 5,000 kJ | 1,195.0287 kcal | kilojoules to kilocalorie (food Calorie) |
| 6,000 kJ | 1,434.0344 kcal | kilojoules to kilocalorie (food Calorie) |
| 8,368 kJ | 2,000 kcal | kilojoules to kilocalorie (food Calorie) |
| 8,700 kJ | 2,079.3499 kcal | kilojoules to kilocalorie (food Calorie) |
| 10,000 kJ | 2,390.0574 kcal | kilojoules to kilocalorie (food Calorie) |
| 12,000 kJ | 2,868.0688 kcal | kilojoules to kilocalorie (food Calorie) |
| 15,000 kJ | 3,585.086 kcal | kilojoules to kilocalorie (food Calorie) |
Units in this converter and their exact factors
| Unit | Symbol | One unit in joules |
|---|---|---|
| joule | J | 1 joule |
| kilojoule | kJ | 1,000 joule |
| megajoule | MJ | 1,000,000 joule |
| calorie (thermochemical) | cal | 4.184 joule |
| kilocalorie (food Calorie) | kcal | 4,184 joule |
| watt-hour | Wh | 3,600 joule |
| kilowatt-hour | kWh | 3,600,000 joule |
| British thermal unit | BTU | 1,055.05585262 joule |
| therm (US) | thm | 105,505,585.262 joule |
| foot-pound | ft·lb | 1.3558179483 joule |
FAQFrequently asked questions about energy conversion
How many Calories in 1,000 kJ?
239 Calories.
What is 8,700 kJ?
About 2,079 Calories — the Australian daily intake reference for an adult.
How do I estimate?
Divide kilojoules by 4.2, or by 4 for a quick over-estimate.
Is a kilojoule a lot?
No — a single biscuit is around 400 kJ, so daily intake runs to thousands.
Why does Australia use kilojoules?
Metrication. The joule is the SI energy unit, and food labelling followed the rest of the system.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Physical Laboratory (NPL) — United Kingdom's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.