Power Converter
Convert power units between watts, kilowatts, horsepower, BTU/hour, and more. Free online power conversion.
About this calculator
Motors and vehicles are rated in horsepower, appliances in watts, air-conditioners in BTU per hour or tons. Convert between watts, kilowatts, megawatts, milliwatts, mechanical horsepower, metric horsepower (PS), BTU per hour and calories per second.
Know which horsepower: mechanical hp is 745.7 W, metric hp (PS, the unit on most Indian and European car brochures) is 735.5 W.
How to use it
- Type the Value.
- Choose the From Unit and To Unit.
- Press Convert.
Factors (to watts)
1 kW = 1,000 W, 1 hp = 745.7 W, 1 PS = 735.499 W, 1 BTU/h = 0.293071 W and 1 cal/s = 4.184 W. Formula: value × from ÷ to.
Worked example
Examples
| 1 kW | 1.341 hp |
| 1 hp | 745.7 W |
| 100 PS (car) | 98.6 hp |
| 18,000 BTU/h (1.5-ton AC) | 5.275 kW |
Tips and common mistakes
- A 1.5-ton air-conditioner is rated 18,000 BTU/h, about 5.3 kW of cooling.
- Power × time = energy: a 1 kW heater for an hour uses 1 kWh.
- Brochure hp can be PS, bhp or kW. Check the label.
- Check the unit when reading a motor plate.
- A person can sustain roughly 100 W for hours.
Frequently asked questions
How many watts are in a horsepower?
745.7 watts.
How many hp is a kilowatt?
1.341.
What is PS?
Pferdestärke, metric horsepower, 735.5 W.
What is a BTU per hour?
A power unit equal to 0.293 W, used for heating and cooling.
How many tons is an air-conditioner?
1 ton of cooling is 12,000 BTU/h or 3.517 kW.
What is the difference between power and energy?
Power is the rate of using energy.