What the Power Converter Does

This power converter changes a power value from one unit to another: watts (W), kilowatts (kW), mechanical horsepower (hp) and metric horsepower (PS). It is built for people who run into more than one power unit and need them to line up.

Typical users include car buyers comparing an engine quoted in hp against one quoted in PS, electricians and homeowners sizing appliances or generators in watts and kilowatts, and students checking physics or engineering homework. Enter a number, pick the units, and read the equivalent value.

How It Works: The Formula

Every conversion runs through one base unit, the watt. The tool first converts your input to watts, then converts watts to the unit you want. The fixed relationships it uses are:

1 kW = 1000 W
1 hp (mechanical) = 745.7 W
1 PS (metric horsepower) = 735.5 W

The Two-Step Calculation

Step 1 converts the input to watts by multiplying by its factor. Step 2 divides those watts by the target unit's factor.

So the general formula is: result = (value x source_factor) / target_factor, where the factor is 1000 for kW, 745.7 for hp, 735.5 for PS, and 1 for W. Because hp and PS are defined slightly differently, the same number of each is not equal: 100 PS is a bit less power than 100 hp.

Worked Example: 150 hp to kW

Suppose a car is rated at 150 hp and you want kilowatts. Step 1: convert to watts. 150 x 745.7 = 111,855 W. Step 2: divide by 1000 to get kW. 111,855 / 1000 = 111.855 kW, which rounds to about 111.9 kW.

Going the other way, a 2.2 kW motor is 2200 W. Divide by 745.7 to get 2.95 hp, or divide by 735.5 to get 2.99 PS. This is why a motor sold as roughly 3 hp and 3 PS describes nearly the same machine.

Tips and Common Mistakes

A few points keep conversions accurate:

Do not treat hp and PS as identical. PS is about 1.4% smaller, so converting carefully matters for engine specs.
Mechanical (imperial) horsepower used here is 745.7 W. Electrical horsepower (746 W) and boiler horsepower are different definitions; check which one a spec sheet means.
Watch the kilo prefix. Mixing up W and kW shifts the answer by a factor of 1000.
Power is not energy. Watts and horsepower measure rate; a watt-hour or kWh measures energy over time and cannot be converted here.
Quoted appliance or engine figures are often rounded, so expect small differences from a precise calculation.