How Many Megajoules in a Kilowatt-Hour?
Quick Answer
There are 3.6 megajoules in one kilowatt-hour.
1 kWh = 3.6 MJ
Understanding the Conversion
One kilowatt-hour equals exactly 3.6 megajoules (MJ). This relationship is clean because 1 kW = 1,000 J/s and 1 hour = 3,600 s, so 1 kWh = 1,000 × 3,600 J = 3,600,000 J = 3.6 MJ. Energy content of fuels is often expressed in MJ/kg.
Formula
1 kWh = 3.6 MJ
Common Examples
| Description | Value |
|---|---|
| A 60W bulb for 1 hour (0.06 kWh) | 0.216 MJ |
| Gasoline energy density | ≈34 MJ/L ≈ 9.4 kWh/L |
| Daily human energy expenditure | ≈8–10 MJ (2,000–2,400 kcal) |
Quick Reference Table
Use this table for quick conversions between kilowatt-hour and megajoules:
| kilowatt-hour | megajoules |
|---|---|
| 1 | 3.6 |
| 2 | 7.2 |
| 5 | 18 |
| 10 | 36 |
| 25 | 90 |
| 50 | 180 |
| 100 | 360 |
Frequently Asked Questions
How Many Megajoules in a Kilowatt-Hour?
There are 3.6 megajoules in one kilowatt-hour. One kilowatt-hour equals exactly 3.6 megajoules (MJ). This relationship is clean because 1 kW = 1,000 J/s and 1 hour = 3,600 s, so 1 kWh = 1,000 × 3,600 J = 3,600,000 J = 3.6 MJ. Energy content of fuels is often expressed in MJ/kg.
What is the formula to convert kilowatt-hour to megajoules?
The formula is: 1 kWh = 3.6 MJ. To convert, multiply the number of kilowatt-hours by 3.6 to get the equivalent in megajoules.
How do I convert megajoules to kilowatt-hour?
To convert megajoules to kilowatt-hour, divide the number of megajoules by 3.6. For example, 18 megajoules equals 5 kilowatt-hours.