Power Converter
Convert watts, kilowatts, horsepower, and BTU per hour.
Conversion sheet
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Power is the rate energy is used — watts on appliances, horsepower on engines, BTU per hour on air conditioners. This converter routes all of them through the watt so you can compare an electric motor and a gas engine on the same scale.
How it works
Power values convert through watts as the base unit.
The watt is the base, defined as one joule per second. Kilowatts and megawatts are simply thousands and millions of watts, used for homes and power plants respectively.
Horsepower is the legacy engine unit: one mechanical horsepower equals 745.7 watts. BTU per hour, common on heating and cooling gear, is about 0.293 watts — so a 12,000 BTU/hr air conditioner moves roughly 3.5 kW of cooling power.
Result = (value × watts-per-source-unit) ÷ watts-per-target-unit.
Worked examples
Convert 1 horsepower to kilowatts. → 0.7457 kilowatts
1 hp = 745.6999 W, divided by 1000 = 0.7457 kW.
Convert a 200 hp engine to kilowatts. → 149.14 kilowatts
200 × 745.6999 = 149,140 W = 149.14 kW.
Tips & gotchas
- A rough rule: 1 kW is about 1.34 horsepower, and 100 hp is about 75 kW — useful for comparing electric and gas vehicle specs.
- Air conditioners labeled in BTU/hr describe cooling capacity, not electrical draw. A 12,000 BTU/hr unit (one 'ton') is about 3.5 kW of cooling but may pull only ~1.2 kW from the wall.
- Don't confuse power (watts) with energy (watt-hours). A 60 W bulb has constant power; its energy use depends on how long it runs.
- Megawatts are for grid-scale figures — a single large wind turbine is often rated around 2–3 MW.
FAQ
How many watts is one horsepower?
About 745.7 watts for mechanical horsepower, the figure used here. Metric horsepower (PS) is slightly less, about 735.5 watts.
What does BTU per hour measure on an air conditioner?
Cooling capacity — how much heat it can remove per hour. One BTU/hr is about 0.293 watts, and 12,000 BTU/hr is commonly called one 'ton' of cooling.
Is a kilowatt the same as a kilowatt-hour?
No. A kilowatt is power (a rate); a kilowatt-hour is energy (a rate sustained for an hour). This tool converts power; use the Energy Converter for kilowatt-hours.
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