Kilowatt to Watt

Free instant kilowatt to watt converter. 1 kW = 1000 W.

1000
Formula
1 kW = 1000 W

Common Kilowatt to Watt values

Common Kilowatt to Watt conversion values.
Kilowatt (kW)Watt (W)
11000
55000
1010000
2525000
5050000
100100000
500500000
10001000000

How does Kilowatt to Watt conversion work?

Type a value in the Kilowatt (kW) field and the equivalent in Watt (W) appears instantly to the right. The math uses the exact formula shown above โ€” no rounding errors, no approximations beyond standard floating-point precision. Use the swap button to flip the units and see the inverse conversion.

Kilowatt. One thousand watts. A typical home AC unit is 2-4 kW; an EV fast charger is 50-350 kW.

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.

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๐ŸŽฏ Accurate conversions

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 โ€” 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 W

Power 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 ftยทlbf/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 โ‰ˆ 0.293 W. ISO 80000-5 codifies these definitions.

Worked examples

Example 1
Car engine
Inputs:
200 HP = ? kW
Output:
200 ร— 745.6998... = 149.14 kW
Example 2
HVAC unit
Inputs:
12,000 BTU/h = ? kW
Output:
12,000 ร— 0.29307107 = 3.517 kW (โ‰ˆ "1 ton" of cooling)
Example 3
Toaster
Inputs:
1.5 kW = ? BTU/h
Output:
1500 / 0.29307107 โ‰ˆ 5,118 BTU/h

Limitations

  • Three "horsepower" variants โ€” mechanical (US car), metric (PS, EU car), electrical (motor nameplate) โ€” differ by ~1.4%; pick the right one for context.
  • Boiler horsepower (used in steam-engine ratings) is yet another unit: 1 bhp โ‰ˆ 9,809.5 W โ€” about 13ร— mechanical HP. Not modeled.
  • BTU/h and tonne-of-refrigeration (1 ton โ‰ˆ 12,000 BTU/h โ‰ˆ 3.517 kW) are HVAC industry units.
  • Audio "watts RMS" and "peak watts" are marketing terms, not converter inputs โ€” 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% โ€” verify which definition matches your source.

Frequently asked

What is the formula for converting Kilowatt to Watt?+
The formula is: 1 kW = 1000 W. Type any value into the calculator above and the result appears instantly.
How do I convert Watt back to Kilowatt?+
Click the swap button (โ‡„) above to go to the Watt โ†’ Kilowatt converter, or use the inverse formula derived from the one shown.
How accurate is the conversion?+
Conversion factors used here are exact rational values from NIST SP 811 and the BIPM SI brochure (e.g. 1 ft = 0.3048 m exactly, 1 lb = 0.45359237 kg exactly). Trailing-digit differences vs hand calculation come only from binary floating-point representation, never from the conversion factor itself.
Where do these conversion factors come from?+
Length and mass factors come from the 1959 international yard-and-pound agreement; SI base units (metre, kilogram, second, kelvin) come from the 2019 BIPM redefinition; energy and pressure factors are NIST SP 811 reference values. Each editorial section above lists the specific source for that category.
Can I copy the conversion factor for use elsewhere?+
Yes. The factor in the formula above is the exact rational value used internally; copying it into Excel or another tool reproduces the result to floating-point precision.

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