Unit converters

Power converter

Convert watts, kilowatts, distinct mechanical, metric and electrical horsepower, and International Table BTU per hour, with local CSV export.

Convert a power rating. Check the definition below each unit, especially when converting horsepower.

Value to convert

Nonnegative decimal or scientific notation, up to 10¹⁵.

From unit

Mechanical horsepower: 550 foot pound-force per second, about 745.699872 W.

To unit

One kilowatt is 1,000 watts.

Swap keeps the numeric value and exchanges its units.

Update while I type

Starts with an example. Edit the value or choose a conversion below.

Try a common conversion

Converted value

—

Choose units and convert to see the equation.

No result yet.

Use result swaps direction and keeps the measured quantity. Undo restores your previous entries.

How this conversion works

Source value × source factor ÷ target factor.

Value in Watts (W): —
Source-to-target multiplier: —

Display uses up to 12 significant digits and six decimal places or scientific notation. CSV preserves the numeric calculation result; arithmetic has finite precision.

This value in every supported unit

All results refer to the same input quantity. A dash means that conversion exceeds numeric precision.

Unit	Value
Convert a value to compare units.

Convert a power quantity

Enter a nonnegative power and choose its precise source definition.
Select the target unit and convert.
Review the watt equivalent and multiplier, then copy or download.

Different horsepower definitions

Mechanical horsepower is 550 ft·lbf/s, approximately 745.699872 W. Metric horsepower is 75 kgf·m/s, exactly 735.49875 W. Electrical horsepower here is 746 W. Choose the definition used by the source; the tool does not infer it from a motor or vehicle name.

One kW is 1000 W, and one International Table BTU per hour is approximately 0.293071 W. Calculation is power × source watt factor ÷ target watt factor. Definitions follow NIST’s power table. Mechanical/metric factors use full international foot, pound-force and standard-gravity definitions; the full IT BTU factor is divided by 3600 seconds.

Supported power definitions
Unit	Watts per unit
Milliwatts (mW)	0.001
Watts (W)	1
Kilowatts (kW)	1000
Megawatts (MW)	1000000
Mechanical horsepower	745.6998715822702
Metric horsepower	735.49875
Electrical horsepower	746
IT BTU per hour	0.2930710701722222

Limits and privacy

Nonnegative source power quantities up to 10¹⁵; arithmetic underflow rejected. Converts units without estimating efficiency, electrical input versus shaft output, motor suitability or appliance consumption. Boiler/water/other horsepower variants, apparent power (VA/kVA) and energy units (Wh/kWh) are not supported.

Display uses up to 12 significant digits and six decimal places or scientific notation; CSV retains the finite floating-point result. Inputs stay in browser memory without requests, uploads or saved ratings. Live conversion updates after a 300 ms pause. Compare all eight supported definitions and download their numeric results. Swap keeps the input number and exchanges units; Use result keeps the unrounded converted quantity and reverses direction. Those actions, examples and Reset have one Undo step; editing inputs clears that action history. Reset clears output and restores one mechanical horsepower to kW.

Can kVA be converted to kW with one factor?

For AC quantities the relationship depends on power factor. This tool converts power units with fixed definitions and does not assume a power factor.

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