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Energy
Joules to Megajoules
Convert joules (J) to megajoules (MJ). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 J = 1.0000e-6 MJ
Joules to Megajoules Conversion Table
Common values, ready to copy:
| joules | megajoules |
|---|---|
| 1 J | 1.0000e-6 MJ |
| 2 J | 2.0000e-6 MJ |
| 5 J | 5.0000e-6 MJ |
| 10 J | 1.0000e-5 MJ |
| 25 J | 2.5000e-5 MJ |
| 50 J | 5.0000e-5 MJ |
| 100 J | 0.0001 MJ |
| 1,000 J | 0.001 MJ |
Formula
megajoules = joules × 0.000001
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 Joules and Megajoules
Joules (J): The SI unit of energy; named for James Prescott Joule, whose 19th-century experiments established the equivalence of mechanical work and heat. Common uses: Physics calculations, food calorie labeling in metric countries (kilojoules), battery capacity, and chemistry.
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.
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 megajoules = joules × 0.000001, 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 joules and megajoules 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.