Watts to Milliwatts Converter
Convert watt to milliwatt instantly. 1 W = 1000 mW, worked steps and a full reference table.
How to use it
- Type the value in watt — the result updates as you type.
- Use Swap to flip the direction, or change either dropdown to convert between any two units.
- Click the result to copy it. The URL updates too, so you can bookmark or share the exact conversion.
Examples
| 1 W | 1000 mW |
| 5 W | 5000 mW |
| 10 W | 10000 mW |
| 100 W | 100000 mW |
One watt equals 1000 milliwatts (mW). To convert watts to milliwatts, multiply by 1000; to go back the other way, multiply by 0.001 instead.
The converter above does it as you type and shows the working underneath, so you can check the arithmetic rather than take the number on trust.
What watts and milliwatts actually measure
Watt (W) — The watt is the SI unit of power — one joule per second. Light bulbs, appliances, audio equipment and solar panels.
Milliwatt (mW) — A milliwatt is a thousandth of a watt. Laser pointers, radio transmit power and low-power electronics.
Watts to Milliwatts conversion table
The most common values, worked out in advance. Anything not listed can be typed straight into the converter.
| W | mW |
|---|---|
| 1 W | 1000 mW |
| 2 W | 2000 mW |
| 5 W | 5000 mW |
| 10 W | 10000 mW |
| 25 W | 25000 mW |
| 50 W | 50000 mW |
| 100 W | 100000 mW |
How to convert watts to milliwatts by hand
Multiply the number of watts by 1000.
For example, 25 W × 1000 = 25000 mW.
Going the other way, divide by 1000 — or multiply by 0.001, which is the same thing and easier to do in your head.
Everything runs in your browser
There is no server involved in the calculation. The numbers you type never leave your device, nothing is logged, and the page keeps working with no connection once it has loaded. That is not a marketing line — it is simply how the tool is built, because a calculation like this has no reason to touch a network.
Questions people ask
How many mW are in 1 W?
1 W equals exactly 1000 mW. Multiply any value in watt by 1000 to get milliwatt.
Is anything uploaded to a server?
No. The whole calculation happens in your browser. Nothing is sent anywhere, and the page keeps working offline once loaded.
Last updated 18 August 2026