Power Converter

ConversionEdited by Hemant Kumar and Anjita Rai, founders · How we checkUpdated Free · No sign-up

Quick answer: Choose a starting unit and a target unit, then enter a value. Common conversions: 1 kW = 1.341022 hp; 1 W = 0.001 kW; 1 W = 0.001341022 hp. This converter covers 9 power units.

Use the Power Converter

Power formula and what each symbol means

target = value × (factor of starting unit ÷ factor of target unit), where each factor is the unit value in W.

Symbols used in the formula
SymbolMeaning
valueThe number you want to convert
factorThe unit’s size expressed in the base unit (W)

Power examples

kW to hp

10 kW = 13.41022 hp.

W to kW

10 W = 0.01 kW.

W to hp

10 W = 0.01341022 hp.

How to calculate Power step by step

  1. Choose the starting unit and the target unit.
  2. Enter your value.
  3. Read the converted value, plus the conversion factor in both directions.

Popular power conversions

How to read your Power result

Power is energy per time. One watt is one joule per second. Mechanical horsepower is about 745.7 W while metric horsepower (PS) is exactly 735.49875 W, so check which one a car or motor spec uses.

UNITSYMBOLEQUALSVALUE OF 1 W
WattW1 W = 1 W1 W
KilowattkW1 kW = 1,000 W0.001 kW
MegawattMW1 MW = 1,000,000 W0.000001 MW
Horsepower (mechanical)hp1 hp = 745.69987 W0.001341022 hp
Metric horsepowerPS1 PS = 735.49875 W0.001359622 PS
BTU per hourBtu/h1 Btu/h = 0.29307107 W3.412142 Btu/h
Ton of refrigerationTR1 TR = 3,516.8533 W0.0002843451 TR
Erg per seconderg/s1 erg/s = 1×10⁻⁷ W10,000,000 erg/s
Foot pound-force per secondft·lbf/s1 ft·lbf/s = 1.3558179 W0.7375621 ft·lbf/s

Common mistakes when calculating Power

  • Assuming all horsepower figures are the same: mechanical hp is about 1.4% larger than metric PS.
  • Mixing kW (power) with kWh (energy).
  • Using Btu/h for heating loads without noting that 1 ton of refrigeration is 12,000 Btu/h.

Power FAQ

How many watts are in a horsepower?

One mechanical horsepower is about 745.7 watts.

How many kW is 1 PS?

One metric horsepower is exactly 0.73549875 kW.

How many watts is a ton of refrigeration?

One ton of refrigeration is about 3,516.85 watts (12,000 Btu/h).

What is the base unit for power?

This converter uses watt (W) as the common base unit: every value is first converted to it and then to the target unit.

How do I convert between two power units?

Choose the starting and target units, enter the value and read the result. By hand: convert to the base unit with the table, then divide by the target unit factor.

How many horsepower are in 1 kilowatt?

1 kW = 1.341022 hp.

How many kW are in 1 watt?

1 W = 0.001 kW.

How many horsepower are in 1 watt?

1 W = 0.001341022 hp.

Which power units does this converter support?

It covers 9 units: watt (W), kilowatt (kW), megawatt (MW), horsepower (hp), metric horsepower (PS), BTU per hour (Btu/h), ton of refrigeration (TR), erg per second (erg/s), foot pound-force per second (ft·lbf/s).

How accurate is the power converter?

Results are calculated at full double precision and shown to about 8 significant figures. Round the answer to the precision of your original measurement; a result cannot be more accurate than the number you started with.

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Method, review and disclaimer

Edited by: Hemant Kumar and Anjita Rai, founders of ToolsVault (SEO and content professional, not a licensed adviser). Method: this tool runs in your browser using the formula shown on this page; the numbers you enter are not sent to our servers. Sources: NIST SP 811, Appendix B.8: conversion factors