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Watt (W) Converter

Type a power figure, choose the unit it is written in, and press Convert to see the same power expressed in the other units the tool lists.

What the watt converter does

The form has two inputs and one action: a Power box that takes a number, a Unit list that says which unit that number is written in, and a Convert button. The unit choices are Milliwatts (mW), Watts (W), Kilowatts (kW), Megawatts (MW), Gigawatts (GW), Decibel-milliwatts (dBm) and Decibel-watts (dBW).

Nothing is worked out until you press Convert. The answers then show up as cards below the button. Copy takes a result and its unit and puts them on the clipboard, and Clear resets the form, returning Unit to Watts (W). The whole thing runs in the page itself, so the figure you type is not sent off anywhere.

Watt conversion formulas

The metric units are spaced by a factor of 1000. Milliwatts sit one step below watts, so a watt figure turns into milliwatts by multiplying by 1000; kilowatts sit one step above watts, so a watt figure turns into kilowatts by dividing by 1000. Putting in Power: 2, Unit: Watts (W) comes back as Milliwatts: 2000 mW; Watts: 2 W; Kilowatts: 0.002 kW; Megawatts: 0.000002 MW.

Megawatts and gigawatts continue the same ladder of steps upward, which is why Power: 1, Unit: Kilowatts (kW) reads back as Milliwatts: 1000000 mW; Watts: 1000 W; Kilowatts: 1 kW; Megawatts: 0.001 MW, and a single watt is small next to a megawatt: Power: 1, Unit: Watts (W) gives Milliwatts: 1000 mW; Watts: 1 W; Kilowatts: 0.001 kW; Megawatts: 0.000001 MW.

The two decibel units are not part of that ladder - they are logarithmic power scales, so they are not reached by a single multiplier. The worked results show where they land: Power: 0, Unit: Decibel-milliwatts (dBm) returns Milliwatts: 1 mW; Watts: 0.001 W; Kilowatts: 0.000001 kW; Megawatts: 0.000000001 MW, and Power: 0, Unit: Decibel-watts (dBW) returns Milliwatts: 1000 mW; Watts: 1 W; Kilowatts: 0.001 kW; Megawatts: 0.000001 MW.