Power Converter

Convert power between watts, kilowatts, horsepower, BTU per hour, tons of refrigeration and other units.

How to use the Power Converter

  1. Type the value you want to convert in the first box.
  2. Choose the unit you are converting from and the unit you want to convert to.
  3. Read the result instantly. Use the swap button to reverse the direction, or copy the result with one click.

Popular power conversions

ConversionResultFormula
Kilowatts to horsepower1 kW = 1.34102 hphorsepower = kilowatts × 1.3410221
Horsepower to kilowatts1 hp = 0.7457 kWkilowatts = horsepower × 0.74569987
Watts to horsepower1 W = 0.00134102 hphorsepower = watts × 0.0013410221
Horsepower to watts1 hp = 745.7 Wwatts = horsepower × 745.69987
BTU per hour to watts1 BTU/h = 0.293071 Wwatts = BTU per hour × 0.29307107
Watts to BTU per hour1 W = 3.41214 BTU/hBTU per hour = watts × 3.4121416
BTU per hour to kilowatts1 BTU/h = 0.000293071 kWkilowatts = BTU per hour × 0.00029307107
Kilowatts to BTU per hour1 kW = 3,412.14 BTU/hBTU per hour = kilowatts × 3,412.1416
Tons of refrigeration to kilowatts1 TR = 3.51685 kWkilowatts = tons of refrigeration × 3.5168528
Kilowatts to tons of refrigeration1 kW = 0.284345 TRtons of refrigeration = kilowatts × 0.28434514
Kilowatts to metric horsepower1 kW = 1.35962 PSmetric horsepower = kilowatts × 1.3596216
Metric horsepower to kilowatts1 PS = 0.735499 kWkilowatts = metric horsepower × 0.73549875
Horsepower to metric horsepower1 hp = 1.01387 PSmetric horsepower = horsepower × 1.0138697
Metric horsepower to horsepower1 PS = 0.98632 hphorsepower = metric horsepower × 0.98632007
Tons of refrigeration to BTU per hour1 TR = 12,000 BTU/hBTU per hour = tons of refrigeration × 12,000
BTU per hour to tons of refrigeration1 BTU/h = 0.0000833333 TRtons of refrigeration = BTU per hour ÷ 12,000
Watts to kilowatts1 W = 0.001 kWkilowatts = watts ÷ 1,000
Kilowatts to watts1 kW = 1,000 Wwatts = kilowatts × 1,000

Supported power units

UnitSymbolEqual to
WattW1 W
MilliwattmW0.001 W
KilowattkW1,000 W
MegawattMW1,000,000 W
GigawattGW1,000,000,000 W
Horsepower (mechanical)hp745.69987 W
Metric horsepowerPS735.49875 W
Electrical horsepowerhp(E)746 W
BTU per hourBTU/h0.29307107 W
Ton of refrigerationTR3,516.8528 W
Kilocalorie per hourkcal/h1.1622222 W
Foot-pound per secondft·lbf/s1.3558179 W
Joule per secondJ/s1 W

Power is energy per time

Power measures how fast energy is used or produced. One watt is one joule per second. A 60 W bulb uses 60 joules every second; a 2 kW heater uses 2,000.

Horsepower comes in several sizes

  • Mechanical (imperial) horsepower: 745.7 W, used for engines in the US and UK.
  • Metric horsepower (PS, CV, cv): 735.5 W, used in Europe and Asia.
  • Electrical horsepower: exactly 746 W, used for electric motors.

Air conditioning

Cooling capacity is rated in BTU per hour or tons of refrigeration. One ton is 12,000 BTU/h, about 3.517 kW. A “1.5 ton” air conditioner therefore removes about 18,000 BTU of heat per hour.

Frequently asked questions

How many watts are in one horsepower?

One mechanical horsepower is about 745.7 watts. One metric horsepower (PS) is about 735.5 watts.

How do I convert kW to hp?

Multiply kilowatts by 1.34102 for mechanical horsepower, or by 1.35962 for metric horsepower.

How many BTU/h is one ton of air conditioning?

One ton of refrigeration is 12,000 BTU per hour, or about 3.517 kW.

What is the difference between kW and kWh?

A kilowatt (kW) is power, the rate of using energy. A kilowatt-hour (kWh) is energy, the amount used by 1 kW running for one hour.

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