How to convert kilowatt-hours to megajoules
One kilowatt-hour equals 3.6 megajoules, so multiply the number of kilowatt-hours by 3.6:
MJ = kWh × 3.6
kWh = MJ ÷ 3.6 (1 MJ = 0.277778 kWh)
Example: 10 kWh → 10 × 3.6 = 36 MJ.
Going the other way, divide by 3.6, or multiply by 0.277778; the megajoules to kilowatt-hours converter does it for you.
Everyday values
| Kilowatt-hours | Megajoules | For example |
|---|---|---|
| 1 kWh | 3.6 MJ | one kilowatt-hour |
| 10 kWh | 36 MJ | 10 kWh |
| 100 kWh | 360 MJ | 100 kWh |
When you need this conversion
One kWh is exactly 3.6 MJ. Energy statistics and fuel energy content are often given in megajoules: a litre of petrol contains roughly 32–35 MJ, about 9 kWh.
Kilowatt-hour to megajoule conversion table
| kWh | MJ | kWh | MJ |
|---|---|---|---|
| 1 kWh | 3.6 MJ | 13 kWh | 46.8 MJ |
| 2 kWh | 7.2 MJ | 14 kWh | 50.4 MJ |
| 3 kWh | 10.8 MJ | 15 kWh | 54 MJ |
| 4 kWh | 14.4 MJ | 16 kWh | 57.6 MJ |
| 5 kWh | 18 MJ | 17 kWh | 61.2 MJ |
| 6 kWh | 21.6 MJ | 18 kWh | 64.8 MJ |
| 7 kWh | 25.2 MJ | 19 kWh | 68.4 MJ |
| 8 kWh | 28.8 MJ | 20 kWh | 72 MJ |
| 9 kWh | 32.4 MJ | 21 kWh | 75.6 MJ |
| 10 kWh | 36 MJ | 22 kWh | 79.2 MJ |
| 11 kWh | 39.6 MJ | 23 kWh | 82.8 MJ |
| 12 kWh | 43.2 MJ | 24 kWh | 86.4 MJ |
About the units
- Kilowatt-hour (kWh): one kilowatt for one hour, 3.6 megajoules; the unit on electricity bills.
- Megajoule (MJ): one million joules.
Both are units of energy. The conversion factor comes from the exact definitions above, so the calculator is exact; results are only rounded for display (up to six significant digits).
Frequently asked questions
How many megajoules are in one kilowatt-hour?
One kilowatt-hour is 3.6 megajoules. One megajoule is 0.277778 kilowatt-hours.
How do I convert kilowatt-hours to megajoules?
Multiply the value in kilowatt-hours by 3.6. To go back, divide by 3.6.
What is 10 kWh in megajoules?
10 kWh = 36 MJ.
What is 100 kWh in megajoules?
100 kWh = 360 MJ.
Sources
- NIST Special Publication 811 (2008), Guide for the Use of the International System of Units (SI), Appendix B: conversion factors.
- NIST Handbook 44 (2024), Appendix C: General tables of units of measurement.
Last reviewed 5 October 2026. Results are estimates; see our disclaimer.