Kilowatt Hours to Megajoules
Type a value in either box to convert between kilowatt hours and megajoules. The factor is 3.6.
| Kilowatt Hours | Megajoules |
|---|---|
| 1 kWh | 3.6 MJ |
| 2 kWh | 7.2 MJ |
| 3 kWh | 10.8 MJ |
| 5 kWh | 18 MJ |
| 10 kWh | 36 MJ |
| 25 kWh | 90 MJ |
| 50 kWh | 180 MJ |
| 100 kWh | 360 MJ |
How to use
- Enter a value in the Kilowatt Hours field.
- The Megajoules figure appears immediately — no button to press.
- Typing in the Megajoules field converts back to Kilowatt Hours the same way.
- Use the reference table for the values that come up most often.
Kilowatt Hours to Megajoules formula
Converting kilowatt hours to megajoules is a single multiplication by 3.6.
MJ = kWh × 3.6
Put another way, one kilowatt-hour is exactly 18/5 megajoules.
Why this factor: the kilowatt-hour and the megajoule are both defined against the joule, so dividing one definition by the other gives 3.6 directly. Both definitions are set out in full below.
To go the other way, divide by 3.6 — or use the Megajoules to Kilowatt Hours converter, which is the same calculation reversed.
Worked example
Take 2000 kWh and multiply by the factor 3.6: the result is 7200 MJ.
2000 kWh × 3.6 = 7200 MJ
The converter above does this for any value you type, in either direction.
What is a kilowatt-hour?
A kilowatt-hour is the standard billing unit for electricity — one kilowatt drawn for one hour.
Definition: Exactly 3.6 megajoules.
Where it is used: Electricity bills worldwide, solar generation figures, and electric vehicle battery capacity.
What is a megajoule?
A megajoule is one million joules, used for substantial energy quantities.
Definition: Exactly 1×10⁶ joules. One kilowatt-hour is exactly 3.6 MJ.
Where it is used: Fuel energy content, natural gas billing, and industrial energy accounting.
Kilowatt Hours vs Megajoules
The kilowatt-hour is a specialized unit while the megajoule is a metric unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many megajoules are in a kilowatt-hour?
One kilowatt-hour equals 3.6 megajoules.
What is the formula to convert kilowatt hours to megajoules?
Multiply the number of kilowatt hours by 3.6. To reverse it, divide by 3.6 instead.
How do I convert megajoules back to kilowatt hours?
Divide by 3.6, which is the same as multiplying by 0.277777778.
How many megajoules are in 10 kilowatt hours?
10 kWh works out to 36 MJ.
How is the kilowatt-hour defined?
Exactly 3.6 megajoules.