Megajoules to Kilojoules Converter
Convert megajoules to kilojoules — multiply by a thousand. Results update as you type; exact factors shown.
One megajoule is 1,000 kilojoules — see the exact factor, not a rounded rule of thumb.
How the megajoules to kilojoules 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 |
|---|---|---|
| 0.001 MJ | 1 kJ | megajoules to kilojoules |
| 0.01 MJ | 10 kJ | megajoules to kilojoules |
| 0.1 MJ | 100 kJ | megajoules to kilojoules |
| 1 MJ | 1,000 kJ | megajoule to kilojoules |
| 2 MJ | 2,000 kJ | megajoules to kilojoules |
| 3.6 MJ | 3,600 kJ | megajoules to kilojoules |
| 5 MJ | 5,000 kJ | megajoules to kilojoules |
| 8.7 MJ | 8,700 kJ | megajoules to kilojoules |
| 10 MJ | 10,000 kJ | megajoules to kilojoules |
| 20 MJ | 20,000 kJ | megajoules to kilojoules |
| 50 MJ | 50,000 kJ | megajoules to kilojoules |
| 100 MJ | 100,000 kJ | megajoules to kilojoules |
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?
Exactly 1,000.
What is 8.7 MJ?
8,700 kJ — the Australian daily energy intake reference for an adult.
What is 3.6 MJ?
One kilowatt-hour.
Which do gas bills use?
Megajoules in Australia; kilowatt-hours in the UK. The two differ by a factor of 3.6.
What is 1 MJ in calories?
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.