Kilojoules to Megajoules Converter
Convert kilojoules to megajoules — divide by a thousand. Results update as you type; exact factors shown.
One kilojoule is 0.001 megajoules — see the exact factor, not a rounded rule of thumb.
How the kilojoules to megajoules 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 | 0.1 MJ | kilojoules to megajoules |
| 500 kJ | 0.5 MJ | kilojoules to megajoules |
| 1,000 kJ | 1 MJ | kilojoules to megajoules |
| 2,000 kJ | 2 MJ | kilojoules to megajoules |
| 3,600 kJ | 3.6 MJ | kilojoules to megajoules |
| 5,000 kJ | 5 MJ | kilojoules to megajoules |
| 8,700 kJ | 8.7 MJ | kilojoules to megajoules |
| 10,000 kJ | 10 MJ | kilojoules to megajoules |
| 20,000 kJ | 20 MJ | kilojoules to megajoules |
| 50,000 kJ | 50 MJ | kilojoules to megajoules |
| 100,000 kJ | 100 MJ | kilojoules to megajoules |
| 1,000,000 kJ | 1,000 MJ | kilojoules to megajoules |
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 kilojoules in a megajoule?
1,000.
What is 8,700 kJ?
8.7 MJ — a standard daily energy intake reference.
Why do nutrition labels use kJ?
Because typical food energies land in the hundreds to thousands, which reads well in kilojoules.
What is 3,600 kJ?
3.6 MJ, or one kilowatt-hour.
What is 1 kJ in Calories?
0.239 food Calories.
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.