# Power Converter

Free power converter. Convert between watts, kilowatts, megawatts, horsepower, BTU/hour, and other power units with exact conversion factors.

## What this calculates

Convert between all common power units including watts, kilowatts, megawatts, three types of horsepower, BTU/hour, and more. Essential for automotive, electrical, and HVAC applications.

## Inputs

- **Value** — min 0
- **From** — options: Watt (W), Kilowatt (kW), Megawatt (MW), Horsepower (mechanical), Horsepower (electrical), Horsepower (metric/PS), BTU/hour, Foot-pound/second, Calorie/second
- **To** — options: Watt (W), Kilowatt (kW), Megawatt (MW), Horsepower (mechanical), Horsepower (electrical), Horsepower (metric/PS), BTU/hour, Foot-pound/second, Calorie/second

## Outputs

- **Result** — The converted power value.
- **Conversion** — formatted as text — Step-by-step conversion explanation.

## Details

Power measures the rate of energy transfer. The SI unit is the watt (W), equal to one joule per second.

Key Conversion Factors

- 1 mechanical horsepower = 745.7 W = 550 ft·lbf/s

- 1 metric horsepower (PS) = 735.5 W

- 1 electrical horsepower = 746 W (exact)

- 1 kW = 1.341 mechanical hp

- 1 BTU/hr = 0.2931 W

- 1 ton of cooling = 12,000 BTU/hr = 3,517 W

Types of Horsepower

- Mechanical (Imperial): 550 ft·lbf/s, used in the US/UK

- Metric (PS/CV): 75 kgf·m/s, used in Europe/Asia

- Electrical: exactly 746 W, used for electric motors

The difference between mechanical and metric HP is about 1.4%.

## Frequently Asked Questions

**Q: How do I convert kilowatts to horsepower?**

A: Multiply kW by 1.341 for mechanical horsepower, or by 1.3596 for metric horsepower (PS). For example, 100 kW = 134.1 mechanical hp = 135.96 PS. Always specify which type of horsepower you mean.

**Q: What is the difference between mechanical and metric horsepower?**

A: Mechanical (imperial) horsepower equals 745.7 watts, while metric horsepower (PS or CV) equals 735.5 watts. The difference is about 1.4%. European car specs typically use PS/CV (metric), while US specs use mechanical hp.

**Q: How is horsepower related to actual horses?**

A: James Watt defined horsepower as 550 foot-pounds per second based on how much work a draft horse could sustain. In reality, a horse can briefly output about 14.9 hp at peak, but averages closer to 1 hp over sustained work.

**Q: What is a BTU/hour and where is it used?**

A: BTU/hour measures heating or cooling power. Air conditioners, furnaces, and water heaters are rated in BTU/hr. A 12,000 BTU/hr AC unit equals 1 ton of cooling (3,517 W or about 3.5 kW). A typical home furnace produces 40,000-100,000 BTU/hr.

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Source: https://vastcalc.com/calculators/conversion/power-conversion
Category: Conversion
Last updated: 2026-04-21