The watt is one joule per second.
Watts to Kilowatts Converter — W to kW
Convert Watt (W) to Kilowatt (kW) using the exact conversion factor (1 watt = 0.001 kilowatt). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Watts to Kilowatts converter
Converter
Power Converter
Convert watts, horsepower, refrigeration tons, BTU per hour, and engineering power units.
Context values
Some unit families need one extra value for a physically accurate result.
Kilowatt is 1000 watt units.
Result = input x 1 / 1000.
Power uses the watt as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Watts to Kilowatts
Watt and Kilowatt both describe power output, and the conversion is a routine part of comparing an engine or motor's spec sheet across countries that use different power units. Watt is typically associated with standard scientific and everyday power unit worldwide, while Kilowatt is typically associated with standard power unit worldwide for larger appliances, vehicles, and electrical systems.
Formula
kilowatts = watts × 0.001
This factor comes from each unit's defined relationship to the category's base unit: 1 watt equals 1 base unit, and 1 kilowatt equals 1000 base units, so dividing one by the other gives the direct watt-to-kilowatt factor of 0.001.
Simple example
1 W × 0.001 = 0.001 kW
1 watt = 0.001 kilowatts.
Real-world example
100 W × 0.001 = 0.1 kW
100 watts = 0.1 kilowatts.
Conversion table
| Watt (W) | Kilowatt (kW) |
|---|---|
| 1 W | 0.001 kW |
| 10 W | 0.01 kW |
| 100 W | 0.1 kW |
| 500 W | 0.5 kW |
| 1,000 W | 1 kW |
| 5,000 W | 5 kW |
Reverse conversion: Kilowatt to Watt
0.001 kW × 1000 = 1 W
0.001 kilowatts = 1 watt.
watts = kilowatts × 1000
For a page dedicated to this direction, see Kilowatt to Watt.
Watt vs. Kilowatt
| Aspect | Watt | Kilowatt |
|---|---|---|
| Family | SI derived unit | SI derived (metric prefix) unit |
| Typical use | Electrical appliance power ratings worldwide | Electric vehicle motor power ratings (alongside horsepower) |
| Where it's used | Standard scientific and everyday power unit worldwide | Standard power unit worldwide for larger appliances, vehicles, and electrical systems |
Understanding the Watt
Watt (W) measures power. The watt is the SI derived unit of power: one joule of energy per second. It is classified as a SI derived unit.
Where it's used: Standard scientific and everyday power unit worldwide
Uses of the Watt today
- Electrical appliance power ratings worldwide
- Light bulb brightness-equivalent labeling
- Engine and motor power specifications (alongside horsepower)
History of the Watt
The watt is named after James Watt, whose improvements to the steam engine in the late 18th century were commercially pivotal; ironically, Watt himself used horsepower (a unit he helped popularize) to market his engines. The watt was formally adopted as a unit at the 1889 General Conference on Weights and Measures and became the SI derived unit of power in the 20th century.
Historical origin. Watt was not the invention of a single named person; it developed through the process described above.
Understanding the Kilowatt
Kilowatt (kW) measures power. A kilowatt is 1,000 watts. It is classified as a SI derived (metric prefix) unit.
Where it's used: Standard power unit worldwide for larger appliances, vehicles, and electrical systems
Uses of the Kilowatt today
- Electric vehicle motor power ratings (alongside horsepower)
- Household electrical system and generator capacity
- Industrial motor and equipment power ratings
History of the Kilowatt
The kilowatt follows directly from the watt via the standard SI 'kilo-' prefix, becoming especially prominent with the growth of electrical power generation and distribution in the late 19th and 20th centuries.
Historical origin. Kilowatt was not the invention of a single named person; it developed through the process described above.
Watt — sources
- BIPM SI Brochure — Coherent derived units — Defines the watt as the SI unit of power.
Kilowatt — sources
- BIPM SI Brochure — SI prefixes — Defines 'kilo-' as the prefix for 10³.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many kilowatts are in 1 watt?
1 watt equals 0.001 kilowatts, using the exact defined conversion factor rather than an estimate.
How do I convert watt to kilowatt?
Multiply the watt value by 0.001. The converter above does this instantly to whatever precision you set.
How do I convert kilowatt back to watt?
Use the reverse factor: 1 kilowatt equals 1,000 watts. You can also use the swap control in the converter above to flip the direction instantly.
What is a watt?
Watt (W) measures power. The watt is the SI derived unit of power: one joule of energy per second. It is classified as a SI derived unit.
What is a kilowatt?
Kilowatt (kW) measures power. A kilowatt is 1,000 watts. It is classified as a SI derived (metric prefix) unit.
Is the watt to kilowatt conversion exact?
Yes. Both watt and kilowatt are defined by fixed standards rather than physical artifacts, so the factor of 0.001 used above is exact to as many digits as you choose to display.
Where is the watt still used today?
Standard scientific and everyday power unit worldwide