How to use the power converter
- 1 Type the value you want to convert.
- 2 Choose the unit to convert from and the unit to convert to.
- 3 Press ⇄ to swap the two units.
- 4 Read the result, and see the same power in every other unit in the table below.
Power ratings explained
Power is a rate. To find energy used, multiply power by time, then use the Energy Converter for kWh, joules or BTU. Car power is quoted in kW, hp or PS depending on the market, so convert before comparing.
- Air conditioner tons measure cooling output, not electricity drawn.
- Generators in kVA deliver roughly 80% of that as kW.
- Appliance labels show watts; 1,500 W is 1.5 kW.
Features
Seven power units
W, kW, MW, hp, PS, BTU/h and tons of refrigeration.
Cars and AC
kW to hp for engines, tons to BTU/h for air conditioners.
Exact factors
Mechanical hp of 745.7 W and metric PS of 735.5 W.
When to use it
Car engines
European brochures give power in kW; 100 kW is 134 hp or 136 PS.
Air conditioners
A 1.5 ton AC is 18,000 BTU/h, or 5.3 kW of cooling.
Generators and solar
Generator and inverter ratings are in kW or kVA; a 5 kW load is 6.7 hp. For energy used over time, see the Energy Converter.
Appliances
A 2,000 W kettle is 2 kW; running it for 6 minutes uses 0.2 kWh.
Related Unit tasks
Frequently asked questions
How do I convert kW to hp?
Multiply by 1.341. 75 kW is 100.6 hp.
How do I convert hp to kW?
Multiply by 0.7457. 150 hp is 111.9 kW.
What is the difference between hp and PS?
Mechanical horsepower is 745.7 W; metric horsepower (PS) is 735.5 W, about 1.4% smaller, so a car has slightly more PS than hp.
How many BTU per hour is a ton of AC?
12,000 BTU/h, which is 3.517 kW of cooling.
How many watts is 1 horsepower?
745.7 watts for mechanical horsepower.
Is kW the same as kWh?
No. kW is power, the rate of using energy; kWh is energy, the amount used. A 1 kW heater uses 1 kWh in an hour.
How many kW is a 1 ton inverter AC?
It provides about 3.5 kW of cooling but typically draws only about 1 to 1.2 kW of electricity, because air conditioners move more heat than the power they use.
What is a megawatt?
1,000 kilowatts. Power stations and large solar farms are rated in MW.
What is brake horsepower?
Engine power measured at the crankshaft before losses in the gearbox; it is measured in the same horsepower units.
Are the factors exact?
Yes. Mechanical horsepower, metric horsepower and the BTU have defined values in watts.
What does kVA mean on a generator?
Kilovolt-amperes measure apparent power. Real power in kilowatts is usually about eighty percent of the kVA rating, so a ten kVA generator supplies about eight kilowatts.
How do I work out the running cost of an appliance?
Multiply its power in kilowatts by the hours it runs to get kilowatt-hours, then multiply by your electricity price per unit. A two kilowatt heater running for three hours uses six units.
Is a higher wattage appliance always more expensive to run?
Not always. A higher-power appliance that finishes a job quickly can use less energy overall than a low-power one that runs for much longer. Energy used depends on power and time together.
What size generator do I need?
Add up the power of everything you want to run at the same time, allow extra for motors that draw more when starting, and choose a generator comfortably above the total.
Built and reviewed by Hamza Farooq, founder and lead developer
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