W to mW Converter
Convert W to mW: 1 W = 1,000 mW. Formula, worked example, table of common values and unit definitions.
Result250 mW
1 W = 1,000 mW
0.25 W =
250 mW
Formula
mW = W × 1,000 W = mW × 0.001
Worked example
- 0.25 W × 1,000 = 250 mW
Common values
| W | mW |
|---|---|
| 0.001 | 1 |
| 0.01 | 10 |
| 0.1 | 100 |
| 0.25 | 250 |
| 1 | 1,000 |
| 5 | 5,000 |
| 10 | 10,000 |
Unit definitions
| Unit | Equals | What it is |
|---|---|---|
| W | 1 W | Watt, one joule per second. The SI unit of power. |
| mW | 0.001 W | Milliwatt, a thousandth of a watt. |
Frequently asked questions
How many mW are in one W?
1 W = 1,000 mW.
What is the formula to convert W to mW?
mW = W × 1,000. To go back, W = mW × 0.001.
Is mW the same as MW?
No. A lowercase m is milli (one thousandth) and an uppercase M is mega (one million), so mW and MW differ by a factor of one billion. Check the capitalisation on data sheets.
Related
Opposite direction: mW to W
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