Watt Converter — Power Unit Conversion
Convert any power value between watts, kilowatts, megawatts, gigawatts, milliwatts, horsepower, BTU/h, kcal/h, ft·lbf/s, and cal/s. Useful for electrical engineering, HVAC, and comparing appliance ratings.
From unit
To unit
1,000 W = 1 kW
- 1
Convert to watts
1,000 × 1 = 1,000Multiply by the from-unit's watt equivalent. - 2
Convert to target unit
1,000 ÷ 1,000 = 1
How does this calculator work?
Enter a power value and choose the input and output units. The calculator multiplies by the input unit's watt-equivalent, then divides by the output unit's watt-equivalent. Supports watts, kW, MW, GW, mW, horsepower, BTU/h, kcal/h, ft·lbf/s, and cal/s.
Formula
How this is calculated
Every power unit can be expressed as a fixed multiple of the watt (the SI unit of power). To convert from one unit to another, the calculator first multiplies your input by its conversion factor to obtain the equivalent in watts, then divides by the target unit's factor. For example, 1 mechanical horsepower equals 745.7 W, and 1 BTU/h equals 0.2931 W.
The chain is always: input → watts → target unit, so the same logic works for any pair of supported units without requiring a separate table for every combination. Conversion factors used here are the internationally accepted values (mechanical horsepower, thermochemical calorie).
Note that "horsepower" has several slightly different definitions (mechanical, metric, electrical, boiler); this calculator uses the mechanical / imperial value of 745.69987 W. If you need metric horsepower (735.499 W), adjust by multiplying your result by 745.7 / 735.5 ≈ 1.0138.
Frequently asked questions
One mechanical (imperial) horsepower equals 745.69987 watts. Metric horsepower (PS) equals 735.499 watts — slightly less.
Both measure power (energy per unit time). One watt = one joule per second. One BTU/h (British Thermal Unit per hour) ≈ 0.2931 W. HVAC systems in the US are commonly rated in BTU/h, while the rest of the world uses watts or kilowatts.
Divide by 1000 — 1 MW = 1000 kW. The calculator handles this automatically; just select kW → MW.
Also known as
TG we-Calculate Editorial Team. (2026). Watt Converter — Power Unit Conversion [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/watt-converter
TG we-Calculate Editorial Team. "Watt Converter — Power Unit Conversion." TG we-Calculate. 2026. https://we-calculate.com/calculator/watt-converter.
TG we-Calculate Editorial Team, "Watt Converter — Power Unit Conversion," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/watt-converter
@misc{wecalculate_watt_converter, title = {Watt Converter — Power Unit Conversion}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/watt-converter}}, year = {2026}, note = {TG we-Calculate} }
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