⚡ Power Converter
By ToolNimba Editorial Team · Updated 2026-06-19
Type in any box and every other unit updates instantly.
This power converter changes a value between watts, kilowatts, megawatts, mechanical horsepower, metric horsepower, BTU per hour, and foot-pounds per second. Type a number into any box and every other unit updates at once, so you can read off the equivalent power without doing the maths. It is useful for engines, motors, appliances, air conditioning, and any time a power rating is quoted in a unit you are not used to.
What is the Power Converter?
Power is the rate at which energy is used or produced, that is, energy per unit of time. The SI unit is the watt (W), which equals one joule of energy per second. Every other power unit on this page is just a fixed multiple of the watt, so the cleanest way to convert is to turn whatever you type into watts first, then back out into any other unit. That is exactly how this tool works internally: your input is converted to watts, then to all the other units at once.
Horsepower is the unit most people meet on engines and motors, but there are two common versions and they are not the same. Mechanical (or imperial) horsepower equals about 745.699 watts and is the figure used in the US and UK. Metric horsepower, often written PS or CV, equals about 735.499 watts and is common on European vehicle specifications. The two differ by roughly 1.4 percent, so a 100 hp rating and a 100 PS rating describe slightly different power levels.
The other units cover specific fields. Kilowatts (1,000 watts) and megawatts (1,000,000 watts) scale the watt up for appliances, vehicles, and power stations. BTU per hour is the standard for heating and air-conditioning capacity, where one BTU/h equals about 0.293071 watts, which is why a 12,000 BTU/h air conditioner is also described as roughly 3.5 kW. Foot-pounds per second is a mechanical unit from physics and engineering, with one ft-lb/s equal to about 1.3558 watts. This converter uses standard accepted factors so the results match official sources rather than rough estimates.
When to use it
- Converting a car or motorbike engine rating between horsepower, metric horsepower (PS) and kilowatts.
- Sizing an air conditioner or heater by switching between BTU per hour and kilowatts or watts.
- Translating an appliance or motor nameplate in watts or kW into horsepower for a quick comparison.
- Checking a physics or engineering answer expressed in ft-lb/s against a more familiar unit.
How to use the Power Converter
- Pick the unit you already know your power figure in (for example horsepower).
- Type the number into that unit's box.
- Read the equivalent value from every other box, which updates instantly.
- Clear the box or type a new number to convert a different power value.
Formula & method
Worked examples
Convert 150 horsepower (mechanical) to kilowatts.
- 150 hp to watts: 150 × 745.699 = 111,854.85 W
- 111,854.85 W to kW: 111,854.85 ÷ 1000 = 111.85 kW
Result: 150 hp ≈ 111.85 kW
Convert 2 kW to mechanical horsepower.
- 2 kW to watts: 2 × 1000 = 2000 W
- 2000 W to hp: 2000 ÷ 745.699 = 2.68 hp
Result: 2 kW ≈ 2.68 hp
Convert a 12,000 BTU/h air conditioner to kilowatts.
- 12,000 BTU/h to watts: 12,000 × 0.293071 = 3516.85 W
- 3516.85 W to kW: 3516.85 ÷ 1000 = 3.52 kW
Result: 12,000 BTU/h ≈ 3.52 kW
Conversion factors to watts
| Unit | 1 unit in watts | Note |
|---|---|---|
| Watt (W) | 1 | SI unit, one joule per second |
| Kilowatt (kW) | 1000 | 1,000 watts |
| Megawatt (MW) | 1000000 | 1,000,000 watts |
| Horsepower, mechanical (hp) | 745.699 | Imperial horsepower, US and UK |
| Metric horsepower (PS, CV) | 735.499 | European vehicle ratings |
| BTU per hour (BTU/h) | 0.293071 | Heating and cooling capacity |
| Foot-pound per second (ft-lb/s) | 1.35581795 | Mechanical unit from physics |
Common power values across units (rounded)
| kW | hp (mechanical) | metric hp (PS) | BTU/h |
|---|---|---|---|
| 1 | 1.34 | 1.36 | 3412 |
| 5 | 6.71 | 6.80 | 17,061 |
| 10 | 13.41 | 13.60 | 34,121 |
| 50 | 67.05 | 67.98 | 170,607 |
| 100 | 134.10 | 135.96 | 341,214 |
Common mistakes to avoid
- Treating mechanical and metric horsepower as identical. Mechanical horsepower is about 745.7 watts while metric horsepower (PS) is about 735.5 watts, a difference of roughly 1.4 percent. A 100 PS European engine is about 98.6 mechanical hp, so swapping the two without converting overstates the power.
- Confusing power (kW) with energy (kWh). A kilowatt is a rate of power, while a kilowatt-hour is an amount of energy used over time. A 2 kW heater running for 3 hours uses 6 kWh. This tool converts power units only, not energy.
- Mixing up BTU with BTU per hour. A BTU is a unit of energy, but appliance ratings use BTU per hour, a unit of power. Only BTU/h converts directly to watts here, so make sure the figure on the nameplate is per hour.
- Using a rough factor for precise work. One mechanical horsepower is 745.699 watts, not a round 750, and 1 kW is about 1.34 hp, not 1.3. The shortcuts are fine for a quick estimate, but for accurate results use the full factors, which this tool does automatically.
Glossary
- Watt (W)
- The SI unit of power, equal to one joule of energy transferred per second.
- Kilowatt (kW)
- One thousand watts. Common for appliances, vehicle motors and small generators.
- Megawatt (MW)
- One million watts. Used for large machinery and power station output.
- Mechanical horsepower (hp)
- Imperial horsepower equal to about 745.699 watts, used for engine ratings in the US and UK.
- Metric horsepower (PS)
- A horsepower equal to about 735.499 watts, common on European vehicle specifications, also written CV.
- BTU per hour (BTU/h)
- A power unit for heating and cooling, where one BTU/h is about 0.293071 watts.
- Foot-pound per second (ft-lb/s)
- A mechanical power unit equal to about 1.3558 watts, the work of moving one pound through one foot in one second.
Frequently asked questions
How do I convert watts to horsepower?
Divide the power in watts by 745.699 to get mechanical horsepower, or by 735.499 to get metric horsepower (PS). For example, 2000 watts is about 2.68 hp. This converter does it instantly for any value.
How many watts is 1 horsepower?
One mechanical (imperial) horsepower is about 745.699 watts, and one metric horsepower (PS) is about 735.499 watts. So 1 hp is roughly 0.746 kW.
How do I convert kW to hp?
Multiply kilowatts by about 1.341 to get mechanical horsepower, since 1 kW divided by 745.699 is about 1.341 hp. For metric horsepower, multiply by about 1.360. For example, 100 kW is about 134.1 hp.
What is the difference between hp and metric horsepower (PS)?
Mechanical horsepower equals about 745.699 watts and is used in the US and UK, while metric horsepower (PS or CV) equals about 735.499 watts and is common in Europe. Metric horsepower is about 1.4 percent smaller, so 100 PS equals roughly 98.6 mechanical hp.
How do I convert BTU/h to watts or kW?
Multiply BTU per hour by 0.293071 to get watts, then divide by 1000 for kilowatts. For example, a 12,000 BTU/h air conditioner is about 3517 watts, or roughly 3.52 kW.
Are these power conversions exact?
They use standard accepted factors: 1 hp = 745.699 W, 1 metric hp = 735.499 W, 1 BTU/h = 0.293071 W, and 1 ft-lb/s = 1.35581795 W. Watts, kilowatts and megawatts are exact by definition, so results match official values rather than rough estimates.