Power Converter
Power measures how fast energy is used or produced. It is the rate of doing work, defined as energy transferred per unit of time. One watt equals one joule of energy every second, so a 60-watt bulb consumes 60 joules each second it is on.
Popular Power Conversions
All Power Conversions
Because power spans everything from a tiny LED to a national power grid, the numbers cover an enormous range. People convert power units to compare appliance ratings, size solar panels and generators, read engine or motor specifications, and make sense of electricity bills, where the power a device draws combined with how long it runs determines the energy you pay for.
Power Units Explained
The SI unit of power is the watt (W), equal to one joule per second. The other units here are simply the watt scaled by metric prefixes, so they all relate by clean powers of ten. The milliwatt (mW) is one thousandth of a watt and suits small electronics like sensors and laser pointers. The kilowatt (kW) is 1,000 watts and is the everyday unit for appliances, motors, and home solar systems. The megawatt (MW), 1,000,000 watts, rates power plants, large wind turbines, and industrial loads. The gigawatt (GW), 1,000,000,000 watts, describes grid-scale generation and the output of major power stations.
How to Convert Power Units
All five units are watts scaled by metric prefixes, so converting means moving the decimal point. Treat the watt as the base: 1 mW = 0.001 W, 1 kW = 1,000 W, 1 MW = 1,000,000 W, and 1 GW = 1,000,000,000 W. To convert, change a value to watts first, then divide by the target unit's factor. For example, to turn 2,500 W into kilowatts, divide by 1,000 to get 2.5 kW. To convert 0.75 MW to kilowatts, note 0.75 MW = 750,000 W, then divide by 1,000 to get 750 kW. Going the other way, 3,200 mW = 3.2 W because you divide by 1,000.
Common Uses
- Sizing home solar panels and battery systems in kilowatts
- Comparing the power ratings of appliances and electronics
- Reading motor, engine, and HVAC specifications
- Rating power plants and wind turbines in megawatts
- Describing grid-scale generation capacity in gigawatts
- Estimating electricity use to understand utility bills
Accuracy Tips
Keep power and energy separate: a watt is a rate, while a watt-hour is energy used over time. Watch the prefix carefully, since one slip moves the value by a factor of 1,000 (kW versus MW). When reading device labels, remember power may be marked in watts even for large equipment, so confirm the unit before converting.
Frequently Asked Questions
How many watts are in a kilowatt?
There are exactly 1,000 watts in one kilowatt. So 2 kW equals 2,000 W, and 500 W equals 0.5 kW.
What is the difference between a kilowatt and a kilowatt-hour?
A kilowatt (kW) measures power, the rate of energy use at an instant. A kilowatt-hour (kWh) measures energy, the amount used over time. A 2 kW heater running for 3 hours uses 6 kWh of energy.
How many watts are in a megawatt and a gigawatt?
One megawatt is 1,000,000 watts (1,000 kW), and one gigawatt is 1,000,000,000 watts (1,000 MW or 1,000,000 kW).
Is power the same as energy?
No. Energy is the total amount of work done, while power is how quickly that energy is delivered. Power equals energy divided by time, which is why a watt is defined as one joule per second.
How do I convert milliwatts to watts?
Divide the number of milliwatts by 1,000, since 1 W = 1,000 mW. For example, 250 mW equals 0.25 W.