Joules (J) to Kilowatt-hours (kW·h) Conversion
Joules
The joule (J) is the SI derived unit of energy, work, and heat, defined as the work done when a force of one newton displaces an object by one metre (J = N·m = kg·m²·s⁻²). Named after James Prescott Joule, who established the mechanical equivalent of heat in the 1840s, the joule unifies all forms of energy — mechanical, thermal, electrical, chemical, and nuclear — under one framework. One joule is small: lifting an apple (≈100 g) one metre requires about 1 joule, while a human at rest metabolises approximately 80 joules per second.
Kilowatt-hours
The kilowatt-hour (kW·h) is a unit of energy equal to exactly 3,600,000 joules (3.6 MJ), defined as the energy consumed by a one-kilowatt device operating for one hour. It is the standard unit on electricity bills worldwide. A typical European household consumes approximately 3,500 kWh per year. One kWh powers a 100-watt bulb for 10 hours, charges an electric vehicle by approximately 5–8 km of driving range, or powers the average laptop for about 10 hours.
| Joules (J) | Kilowatt-hours (kW·h) |
|---|---|
| 0.1 J | 0.0000000278 kW·h |
| 1 J | 0.000000278 kW·h |
| 2 J | 0.000000556 kW·h |
| 3 J | 0.000000833 kW·h |
| 5 J | 0.00000139 kW·h |
| 10 J | 0.00000278 kW·h |
| 20 J | 0.00000556 kW·h |
| 30 J | 0.00000833 kW·h |
| 50 J | 0.0000139 kW·h |
| 100 J | 0.0000278 kW·h |
| 1000 J | 0.000278 kW·h |
Frequently Asked Questions (FAQ)
How many kilowatt-hours are in 1 joules?
1 joules (J) is exactly 0.000000278 kilowatt-hours (kW·h).
How do I convert joules to kilowatt-hours?
Multiply the value in joules by 0.000000278 to get the result in kilowatt-hours. Or use the converter above — type any number and see the result instantly.