Calories to Kilocalories Converter
Convert small calories to kilocalories — the distinction that causes most of the confusion around food energy. Results update as you type; exact factors shown.
One calorie (thermochemical) is 0.001 kilocalorie (food Calorie) — see the exact factor, not a rounded rule of thumb.
How the calories to kilocalories 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.
Australia is fully metric under the National Measurement Act 1960; imperial units appear only in trade with the US and in older documents.
Common energy conversions
| From | To | Units |
|---|---|---|
| 100 cal | 0.1 kcal | calorie (thermochemical) to kilocalorie (food Calorie) |
| 500 cal | 0.5 kcal | calorie (thermochemical) to kilocalorie (food Calorie) |
| 1,000 cal | 1 kcal | calorie (thermochemical) to kilocalorie (food Calorie) |
| 2,000 cal | 2 kcal | calorie (thermochemical) to kilocalorie (food Calorie) |
| 5,000 cal | 5 kcal | calorie (thermochemical) to kilocalorie (food Calorie) |
| 10,000 cal | 10 kcal | calorie (thermochemical) to kilocalorie (food Calorie) |
| 50,000 cal | 50 kcal | calorie (thermochemical) to kilocalorie (food Calorie) |
| 100,000 cal | 100 kcal | calorie (thermochemical) to kilocalorie (food Calorie) |
| 200,000 cal | 200 kcal | calorie (thermochemical) to kilocalorie (food Calorie) |
| 500,000 cal | 500 kcal | calorie (thermochemical) to kilocalorie (food Calorie) |
| 1,000,000 cal | 1,000 kcal | calorie (thermochemical) to kilocalorie (food Calorie) |
| 2,000,000 cal | 2,000 kcal | calorie (thermochemical) 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
What is the difference between a calorie and a Calorie?
A small calorie heats one gram of water by one degree; a kilocalorie heats a kilogram. Food labels use kilocalories but often write "calories".
How many calories in a kilocalorie?
Exactly 1,000.
So is a 2,000-calorie diet 2,000 or 2,000,000?
2,000 kilocalories — two million small calories. The label is using the capital-C convention.
Which does science use?
Joules. The calorie survives mainly in nutrition and older chemistry.
What is 1 kcal in kJ?
4.184 kJ.
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 Measurement Institute (NMI) — Australia's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.