# Horsepower to kW Converter > Horsepower to kW converter instantly converts hp to kilowatts and back, mechanical, metric or electrical. Free, private, runs locally in your browser. - **Canonical URL:** https://boringtoolskit.com/horsepower-kw-converter/ - **Category:** Converters - **Evidence level:** authored-methodology - **Reviewed:** 2026-09-20 - **Last verified:** 2026-10-12 - **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request. ## How it works kilowatts = horsepower x 0.7457 (mechanical horsepower), and horsepower = kilowatts / 0.7457. Enter 1 in the Unit field for hp or 2 for kW. This is mechanical horsepower, not metric PS or electrical hp. ## Worked example 1 mechanical hp = 0.7457 kilowatt ยท 1 kilowatt = 1.341 mechanical hp ## Assumptions - Inputs are treated as exact decimal values. - Standard (not historical or survey) unit definitions are used. - The calculation uses the factors at the precision shown in the formula panel; rounding beyond that is display-only and adds no accuracy. ## Common questions ### Why convert through watt instead of directly? Routing every unit through a single base (watt) means each unit needs only one exact factor against the standard, and any pair combines cleanly. Direct pair factors drift apart over time in hand-maintained tables; a base-unit graph cannot. ### Where do these exact factors come from? From published standards (NIST: SP 811 power conversions). Units like the inch are defined exactly (1 in = 2.54 cm since 1959), so conversions between standard units are exact, not approximate. ### How precise is the converted power value? The conversion applies the standard factors shown in the formula panel. The practical limit is your input: the result only regroups the number you entered, so digits beyond your original reading do not add accuracy. Note that 1 hp = 0.74569997 kW and metric PS differs from mechanical hp, so state which horsepower you mean when the figure matters. ## Sources - [SP 811 power conversions](https://www.nist.gov/pml/special-publication-811) --- *Local planning estimate. Verify current terms, rates, and policies before acting.*