How to Convert Watts to Kilowatts (W to kW)
Power conversions help compare car engines in hp and kW, and air-con units rated in BTU/h against their electrical draw in watts. This guide shows how to convert watts into kilowatts by hand, with examples and a quick-reference table.
The conversion
To convert watts to kilowatts, multiply the value by 0.001. To go the other way, divide by the same number (or multiply by 1,000). For a quick estimate, multiply by about 0.001.
Kilowatts = watts × 0.001
Worked examples
- 3 W = 0.003 kW
- 12.5 W = 0.0125 kW
- 75 W = 0.075 kW
Watts to Kilowatts table
| Watts | Kilowatts |
|---|---|
| 1 W | 0.001 kW |
| 2 W | 0.002 kW |
| 5 W | 0.005 kW |
| 10 W | 0.01 kW |
| 20 W | 0.02 kW |
| 25 W | 0.025 kW |
| 50 W | 0.05 kW |
| 100 W | 0.1 kW |
| 250 W | 0.25 kW |
| 500 W | 0.5 kW |
| 1,000 W | 1 kW |
Common questions
Is W to kW exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Kilowatts to Watts converter.
Mistakes to avoid
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
Background
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
Many conversion factors are exact by definition. The inch has been defined as exactly 2.54 centimetres since 1959, and the pound as exactly 0.45359237 kilograms, so conversions involving them can be as precise as you need.
For any value, use the Watts to Kilowatts Converter or browse all power converters.
Run your own numbers: Watts to Kilowatts Converter