Watt to Kilowatt
Free instant watt to kilowatt converter. 1 W = 0.001 kW.
Common Watt to Kilowatt values
| Watt (W) | Kilowatt (kW) |
|---|---|
| 1 | 0.001 |
| 5 | 0.005 |
| 10 | 0.01 |
| 25 | 0.025 |
| 50 | 0.05 |
| 100 | 0.1 |
| 500 | 0.5 |
| 1000 | 1 |
How does Watt to Kilowatt conversion work?
Type a value in the Watt (W) field and the equivalent in Kilowatt (kW) appears instantly to the right. The math uses the exact formula shown above — no rounding errors, no approximations beyond standard floating-point precision. Use the swap button to flip the units and see the inverse conversion.
Watt. The SI unit of power. 1 W = 1 J/s. A typical LED bulb draws 8-15 W; a smartphone charger 5-25 W.
Kilowatt. One thousand watts. A typical home AC unit is 2-4 kW; an EV fast charger is 50-350 kW.
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Conversion factors come from the official standard (NIST, BIPM, ISO definitions where applicable). Values are precise to standard floating-point limits.
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How it works — the formula
1 W = 1 J/s
1 kW = 1,000 W
1 mechanical HP = 745.6998715822702 W (exact, per IEEE/ISO definition)
1 metric HP (PS) = 735.49875 W
1 BTU/h = 0.29307107 WPower is energy per unit time. The SI unit is the watt (1 W = 1 J/s). The "horsepower" exists in several definitions: mechanical (US imperial, 550 ft·lbf/s = 745.6998... W) is standard for US car engines; metric (PS / DIN-PS, 735.49875 W) for European specifications; electrical (746 W exact) for motor nameplates. BTU per hour is the standard for HVAC and heating equipment, with 1 BTU/h ≈ 0.293 W. ISO 80000-5 codifies these definitions.
Worked examples
- Inputs:
- 200 HP = ? kW
- Output:
- 200 × 745.6998... = 149.14 kW
- Inputs:
- 12,000 BTU/h = ? kW
- Output:
- 12,000 × 0.29307107 = 3.517 kW (≈ "1 ton" of cooling)
- Inputs:
- 1.5 kW = ? BTU/h
- Output:
- 1500 / 0.29307107 ≈ 5,118 BTU/h
Limitations
- Three "horsepower" variants — mechanical (US car), metric (PS, EU car), electrical (motor nameplate) — differ by ~1.4%; pick the right one for context.
- Boiler horsepower (used in steam-engine ratings) is yet another unit: 1 bhp ≈ 9,809.5 W — about 13× mechanical HP. Not modeled.
- BTU/h and tonne-of-refrigeration (1 ton ≈ 12,000 BTU/h ≈ 3.517 kW) are HVAC industry units.
- Audio "watts RMS" and "peak watts" are marketing terms, not converter inputs — use the spec's sustained continuous power.
Conversions are exact rational arithmetic between watt-defined units; horsepower variant selection affects results by up to 1.4% — verify which definition matches your source.