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Energy
Megajoules to Kilojoules
Convert megajoules (MJ) to kilojoules (kJ). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 MJ = 1000 kJ
Megajoules to Kilojoules Conversion Table
Common values, ready to copy:
| megajoules | kilojoules |
|---|---|
| 1 MJ | 1000 kJ |
| 2 MJ | 2000 kJ |
| 5 MJ | 5000 kJ |
| 10 MJ | 10000 kJ |
| 25 MJ | 25000 kJ |
| 50 MJ | 50000 kJ |
| 100 MJ | 100000 kJ |
| 1,000 MJ | 1.0000e+6 kJ |
Formula
kilojoules = megajoules × 1000
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
About Megajoules and Kilojoules
Megajoules (MJ): A million joules; the unit for larger-scale energy quantities. Common uses: Daily food intake (a typical adult consumes 8-10 MJ per day), fuel energy content (gasoline ≈ 34 MJ per liter), and industrial energy.
Kilojoules (kJ): A thousand joules; the practical SI energy unit for food and nutrition in metric countries. Common uses: Food energy labeling outside the US, electrical energy in kJ for small batteries, and biology (metabolism).
How the conversion works
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
The exact relationship is kilojoules = megajoules × 1000, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.
When this conversion matters
Converting between megajoules and kilojoules comes up wherever energy measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.