Convert Watt-hours to Kilowatt-hours
1 watt-hour is 0.001 kWh. One watt-hour is exactly 0.001 kilowatt-hours.
One watt-hour is 0.001 kilowatt-hours. To convert watt-hours to kilowatt-hours, multiply by 0.001; to go the other way, divide by 0.001 or multiply by 1000. The factor is exact rather than rounded: it follows from NIST Special Publication 811. One watt sustained for an hour, so exactly 3,600 joules.
Factor checked against the defining standard · How we check
- Watt-hours × 0.001
value * 0.0010.001 kWh
1 watt-hour in every energy unit
| Unit | Value | Exact factor |
|---|---|---|
| joules | 3,600 J | × 3,600 |
| kilojoules | 3.6 kJ | × 3.6 |
| calories | 860.4206501 cal | × 860.420650096 |
| kilocalories | 0.8604206501 kcal | × 0.860420650096 |
| watt-hours (as entered) | 1 Wh | — |
| kilowatt-hours | 0.001 kWh | × 0.001 |
| British thermal units | 3.412141633 BTU | × 3.41214163313 |
| foot-pounds | 2,655.223737 ft·lbf | × 2,655.2237374 |
Factors are entered by hand from NIST Special Publication 811 rather than derived from a units library, so the ones that terminate are exact rather than rounded.
How do you convert watt-hours to kilowatt-hours?
- 1.Take the measurement in watt-hours.
- 2.Multiply by 0.001 — that is how many kilowatt-hours fit in one watt-hour.
- 3.To go back the other way, divide by 0.001, or multiply by 1000.
Worked example: 25 watt-hours to kilowatt-hours
- Formula
- Wh × 0.001 = kWh
- Arithmetic
- 25 × 0.001 = 0.025 kWh
- Answer
- 25 Wh = 0.025 kWh
The factor is exact, so this figure is exact too — only the display is rounded.
Watt-hours to kilowatt-hours conversion table
| Watt-hours | Kilowatt-hours |
|---|---|
| 1 Wh | 0.001 kWh |
| 2 Wh | 0.002 kWh |
| 3 Wh | 0.003 kWh |
| 4 Wh | 0.004 kWh |
| 5 Wh | 0.005 kWh |
| 6 Wh | 0.006 kWh |
| 7 Wh | 0.007 kWh |
| 8 Wh | 0.008 kWh |
| 9 Wh | 0.009 kWh |
| 10 Wh | 0.01 kWh |
| 12 Wh | 0.012 kWh |
| 15 Wh | 0.015 kWh |
| 20 Wh | 0.02 kWh |
| 25 Wh | 0.025 kWh |
| 50 Wh | 0.05 kWh |
| 100 Wh | 0.1 kWh |
| 200 Wh | 0.2 kWh |
| 300 Wh | 0.3 kWh |
| 500 Wh | 0.5 kWh |
| 1000 Wh | 1 kWh |
| 2000 Wh | 2 kWh |
| 5000 Wh | 5 kWh |
| 10000 Wh | 10 kWh |
What is a watt-hour?
One watt sustained for an hour, so exactly 3,600 joules. Battery capacity is quoted here because it is an amount of energy rather than a rate.
What is a kilowatt-hour?
A thousand watt-hours, and the unit every electricity bill is added up in. Exactly 3.6 megajoules, and the reason a 100 W bulb left on for ten hours costs one unit.
How many kilowatt-hours are in a watt-hour?
One watt-hour is 0.001 kilowatt-hours, exactly. Going the other way, one kilowatt-hour is 1000 watt-hours. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every energy unit here
| Unit | Symbol | One of these is |
|---|---|---|
| Joules | J | the base unit |
| Kilojoules | kJ | 1000 joule |
| Calories | cal | 4.184 joule |
| Kilocalories | kcal | 4184 joule |
| Watt-hours | Wh | 3600 joule |
| Kilowatt-hours | kWh | 3600000 joule |
| British thermal units | BTU | 1055.0559 joule |
| Foot-pounds | ft·lbf | 1.3558179 joule |
Source: NIST Special Publication 811 — the thermochemical calorie is exactly 4.184 J
Questions people actually ask
- How many kilowatt-hours are in a watt-hour?
- 0.001. A thousand watt-hours, and the unit every electricity bill is added up in. Exactly 3.6 megajoules, and the reason a 100 W bulb left on for ten hours costs one unit.
- How do I convert kilowatt-hours back to watt-hours?
- Divide by 0.001, or multiply by 1000 — they are the same operation.
Other energy conversions
Kilowatt-hours to watt-hours — the same conversion the other way.