Power Unit Converter

Motor nameplates, pump curves and compressor datasheets quote power in kilowatts on one and horsepower on another, while a European document adds metric PS and an HVAC sheet adds BTU/h. This converter moves exactly between them with no approximation.

Convert power unit units

Value

From

Why power units collide

Power is energy per time, and three conventions describe it: the SI watt, the mechanical horsepower and metric PS (both near 0.75 kW), and the thermal BTU/h used in refrigeration and HVAC. The mechanical horsepower (745.7 W) and metric PS (735.5 W) differ by about 1.4%, so they must not be swapped blindly.

All factors are exact definitions, so the converter is exact. The only trap is which horsepower — this tool uses the mechanical (imperial) hp; the metric PS is listed separately so you can see the gap.

Which unit where

Kilowatts and megawatts are the SI language of motor and plant ratings; horsepower dominates US pump and compressor nameplates; PS appears on European engine and pump data; BTU/h is the HVAC and refrigeration unit. Match the unit your spec writes in, then convert for comparison.

Complete conversion reference

Convert 1 unit to	W	kW	MW	hp	PS	BTU/h
1 W	1	0.001	1e-06	0.00134102	0.00135962	3.41214
1 kW	1000	1	0.001	1.34102	1.35962	3412.14
1 MW	1e+06	1000	1	1341.02	1359.62	3.41214e+06
1 hp	745.7	0.7457	0.0007457	1	1.01387	2544.43
1 PS	735.499	0.735499	0.000735499	0.98632	1	2509.63
1 BTU/h	0.293071	0.000293071	2.93071e-07	0.000393015	0.000398466	1

Instruments for this measurement

SE10A

Electromagnetic flowmeter, 24V DC

Lining PTFE/PU · DN10–1200

SV21

Vortex flowmeter, steam / gas / liquid

DN15–300 · no moving parts

SG61

Coriolis mass flowmeter

Direct mass & density

S3000CG

Gauge pressure transmitter

0–0.6 … 0–60 MPa

Process Measurement

Flow, pressure, level & temperature

Electromagnetic / vortex / TX

Models shown are representative families, not a complete catalogue. Send us your application, water analysis and installation constraints and we will match instruments to it.

Frequently asked

How many watts in one horsepower?

Exactly 745.7 W for the mechanical (imperial) horsepower. The metric PS is 735.5 W — about 1.4% less — so confirm which one a nameplate means before converting a motor rating.

What is 1 kW in hp and PS?

One kilowatt is 1.341 hp or 1.360 PS. Pump and compressor curves in US markets often quote hp, while European ones quote PS; the converter keeps both so you can compare directly.

Is BTU/h the same as watts?

No. One BTU/h is about 0.293 W (or 3.412 BTU/h per watt). BTU/h is the HVAC and refrigeration power unit; convert it to watts for any electrical or SI calculation.

Why does my pump curve use hp but the panel uses kW?

US pump performance is traditionally in hp, while the electrical panel and plant metering use kW. Convert at the interface rather than mixing them in one efficiency calc.

This page performs exact unit arithmetic with no physical assumption beyond the stated reference (for example mH₂O assumes water near 4 °C, and pH follows its logarithmic definition). It is a working aid, not a substitute for the measurement method named in your permit.