⚡ Power Converter
Convert between watts (W), kilowatts (kW), horsepower (hp/PS), BTU per hour, and other power units in real time. Useful for comparing car spec sheets, or comparing appliance and power-tool wattage against engine output.
How to use
- Enter a value into any power unit field (W, kW, hp, PS, or BTU/h).
- The converted values appear instantly in the other unit fields.
How the calculation works
Power is the rate at which energy is used or produced. Its SI unit is the watt (W = J/s), which lets you compare an appliance's consumption and an engine's output on the same scale. There are two horsepowers. Mechanical horsepower (hp) is about 745.7 W; metric horsepower (PS) is about 735.5 W, roughly 1.4% smaller. Japanese car brochures mainly use PS, now usually alongside kW. BTU per hour (BTU/h) is about 0.293 W. American air conditioners often state cooling capacity in BTU/h, so a "12,000 BTU" unit is about 3.5 kW.
Worked example
An engine rated at 100 PS kW: 100 × 735.5 ÷ 1,000 = 73.55 kW hp: 100 × 735.5 ÷ 745.7 ≈ 98.6 hp The same engine shows a smaller number in hp than in PS. A US air conditioner rated 12,000 BTU/h delivers 12,000 × 0.29307 ≈ 3,517 W, comparable to a 3.5 kW-class Japanese unit.
Things to be aware of
- hp and PS are close but different. Check which one a brochure means when comparing markets.
- An air conditioner's capacity is the heat it removes, which is not the same as its electrical consumption.
- Engine output figures also depend on the measurement standard used (gross or net).
- Power multiplied by time is energy: a 1 kW device running for an hour uses 1 kWh.
FAQ
What's the difference between hp and PS?
hp (horsepower) is mainly used in the US and UK, while PS (metric horsepower) is common in Japanese and European car catalogs. They're close in value but not identical.
Can I use this for air conditioner capacity ratings?
Yes — it's handy for comparing a BTU/h rating on an imported air conditioner with a wattage rating on a domestic one.
Is this useful for comparing car spec sheets?
Yes — you can convert between a kW rating and a PS/hp horsepower rating to compare specs across markets.