Kilojoule is 1000 joule units.
Kilojoules to Megajoules Converter — kJ to MJ
Convert Kilojoule (kJ) to Megajoule (MJ) using the exact conversion factor (1 kilojoule = 0.001 megajoule). See the formula, worked examples, and conversion table.
Kilojoules to Megajoules converter
Converter
Energy Converter
Convert joules, calories, kilowatt-hours, BTU, electronvolts, therms, and mechanical work units.
Context values
Some unit families need one extra value for a physically accurate result.
Megajoule is 1000000 joule units.
Result = input x 1000 / 1e+6.
Energy uses the joule as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Kilojoules to Megajoules
Kilojoule and Megajoule both measure energy, and the conversion is especially useful for comparing nutrition labels (kilocalories) against scientific energy figures (joules). Specifically: Kilojoule is 1000 joule units, and megajoule is 1000000 joule units.
Formula
megajoules = kilojoules × 0.001
This factor comes from each unit's defined relationship to the category's base unit: 1 kilojoule equals 1000 base units, and 1 megajoule equals 1000000 base units, so dividing one by the other gives the direct kilojoule-to-megajoule factor of 0.001.
Simple example
1 kJ × 0.001 = 0.001 MJ
1 kilojoule = 0.001 megajoules.
Real-world example
100 kJ × 0.001 = 0.1 MJ
100 kilojoules = 0.1 megajoules.
Conversion table
| Kilojoule (kJ) | Megajoule (MJ) |
|---|---|
| 1 kJ | 0.001 MJ |
| 10 kJ | 0.01 MJ |
| 100 kJ | 0.1 MJ |
| 500 kJ | 0.5 MJ |
| 1,000 kJ | 1 MJ |
| 2,000 kJ | 2 MJ |
Reverse conversion: Megajoule to Kilojoule
0.001 MJ × 1000 = 1 kJ
0.001 megajoules = 1 kilojoule.
kilojoules = megajoules × 1000
For a page dedicated to this direction, see Megajoule to Kilojoule.
Understanding the Kilojoule (kJ)
Kilojoule is 1000 joule units.
Understanding the Megajoule (MJ)
Megajoule is 1000000 joule units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many megajoules are in 1 kilojoule?
1 kilojoule equals 0.001 megajoules, using the exact defined conversion factor rather than an estimate.
How do I convert kilojoule to megajoule?
Multiply the kilojoule value by 0.001. The converter above does this instantly to whatever precision you set.
How do I convert megajoule back to kilojoule?
Use the reverse factor: 1 megajoule equals 1,000 kilojoules. You can also use the swap control in the converter above to flip the direction instantly.
What is a kilojoule?
Kilojoule (kJ) is a unit of energy.
What is a megajoule?
Megajoule (MJ) is a unit of energy.
Is the kilojoule to megajoule conversion exact?
Yes. Both kilojoule and megajoule are defined by fixed standards rather than physical artifacts, so the factor of 0.001 used above is exact to as many digits as you choose to display.