Skip to content
BuildWire Calc
All tools

Power

Wire & cable

Conduit & loads

Motors & gensets

kW to HP Converter

Convert kilowatts to horsepower with the definition you need, or turn motor output kW into input kW with efficiency.

Free · runs in your browser · nothing is uploaded

Open on BuildWire Calc

This embed was switched off for this website. Open on BuildWire Calc

Add this tool to your siteFree embed code, no sign-up. Keep the credit link.

Embed this tool

Copy this code into your website, blog or class page. The tool runs inside your page.

Optional settings, added to the address after embed=1: &accent=0f6b5c (colour, 3 or 6 hex digits). Other parameters are ignored.

Please keep the credit link below the tool.

One kilowatt is 1.341 mechanical horsepower, so to convert kW to hp you multiply by 1.341, or divide the watts by 745.7. A 7.5 kW motor is therefore 10.06 hp. Type a value, pick the horsepower definition, and the answer appears at once. Three definitions are built in: mechanical hp of 745.7 W, used for US motors and equipment, metric hp of 735.5 W, common on European engine data, and electrical hp of exactly 746 W. Switch to “hp to kW” to go the other way. A motor option treats the figure as shaft output and adds the electrical input for the efficiency you type. Two tables follow the result.
Kw to hp example

How to use the kW to HP Converter

  1. In Convert, keep “kW to hp”, or choose “hp to kW” if you start from horsepower.
  2. Type the number into Value. It is read as kW or hp, depending on the choice above.
  3. Pick the Horsepower type: “Mechanical hp (745.7 W)”, “Metric hp (735.5 W)” or “Electrical hp (746 W)”. Use mechanical for US motors and equipment unless the label says otherwise.
  4. If the number is a motor’s shaft output, tick This is a motor shaft output (show the electrical input).
  5. Enter the Motor efficiency (%) from the nameplate. The box appears only after the tick.
  6. Read Power in hp (or Power in kW in the reverse mode). With the motor box ticked, Electrical input power and Electrical input in hp are added.
  7. Look at the two tables: your value in all three horsepower definitions, and 26 common motor sizes from 0.18 kW to 200 kW.

Four example buttons load cases such as “7.5 kW to hp” and “22 kW motor, 93 % efficient”. “Copy result” copies the answer, “Copy link” copies a link with your inputs, “Print / save as PDF” prints it, and Reset brings back the defaults.

Changing any field updates the result rows, the steps and the tables straight away, and Copy link keeps your exact inputs in the address so you can share or reopen the calculation.

How do you convert kW to hp?

Multiply the kilowatts by 1,000 to get watts, then divide by the watts in one horsepower. For mechanical horsepower that number is 745.69987 W, which makes 1 kW equal to 1.341 hp. A 7.5 kW motor works out to 7,500 ÷ 745.69987 = 10.058 hp, and a 22 kW motor to 29.5 hp.

  1. Write the power in kW, for example 7.5.
  2. Multiply by 1,000: 7,500 W.
  3. Divide by the watts per hp of the definition you need.
  4. Round as needed. The tool shows 10.06 hp for this input.

To go from hp to kW, reverse the steps: multiply the horsepower by the watts per hp and divide by 1,000. One mechanical hp is 0.7457 kW.

How many kW are in 1 hp?

One mechanical horsepower is 0.7457 kW (745.7 W). A metric horsepower is 0.7355 kW, and an electrical horsepower is 0.746 kW. The three are within about 1.4 % of each other, but the gap matters when you compare a European engine rating with a US motor.

The tool’s table for 1 kW and 7.5 kW shows how far apart they are:

DefinitionWatts per hphp in 1 kWhp in 7.5 kW
Mechanical hp745.699871.34110.058
Metric hp735.498751.36010.197
Electrical hp7461.34010.054

Whichever definition you use, a kilowatt is the larger unit: 1 kW is about one and a third horsepower, so a motor’s hp figure is always higher than its kW figure.

What does a kW to hp conversion table show?

A conversion table lists standard motor sizes in kW next to their horsepower. The table under the result covers 26 sizes from 0.18 kW to 200 kW in the definition you picked. A few rows in mechanical hp, as the tool computes them:

Motor size (kW)Horsepower
0.751.006
1.52.012
34.023
7.510.058
1520.115
3749.618
75100.58

The column changes when you switch the horsepower type, so the same table also works for metric hp.

Worked examples

InputResult
7.5 kW, Mechanical hp (745.7 W)10.06 hp
1 kW, Metric hp (735.5 W)1.36 hp
22 kW, Mechanical hp (745.7 W)29.5 hp
5 hp, Electrical hp (746 W)3.73 kW

Calculated by the tool above; open it with the same values to see each step.

Questions, briefly answered

What does kW mean?

kW stands for kilowatt, a unit of power equal to 1,000 watts. Motor nameplates outside the US usually state output in kW, while US nameplates often use hp.

Which horsepower type should I pick?

Use “Mechanical hp (745.7 W)” for US motors and equipment unless the label says otherwise. Choose metric hp when a spec sheet gives PS or CV, and electrical hp only when the document names it.

How does the motor option work?

Tick the motor box and enter the efficiency. The tool divides the shaft output by the efficiency, so a 22 kW motor at 93 % needs 23.66 kW of electrical input, or 31.72 hp.

Can I convert hp back to kW?

Yes. Set Convert to “hp to kW” and enter the horsepower. For example, 5 electrical hp is 3.73 kW.

Why is the kW of a motor different from the power it draws?

The nameplate kW is the mechanical output at the shaft. The motor draws more from the supply because some energy is lost as heat, which is why the efficiency matters.

When do you need to convert kW to hp?

Mostly when two documents use different units, for example a motor rated in kW and a pump or gearbox catalog rated in hp. Converting both to one unit lets you compare them directly.

Why does the tool use 745.69987 W instead of 745.7?

Mechanical horsepower is defined as 550 foot-pounds per second, which is 745.69987 W. The label rounds it to 745.7 W, but the calculation uses the exact figure.