Milliwatt is 0.001 watt units.
Milliwatts to Watts Converter — mW to W
Convert Milliwatt (mW) to Watt (W) using the exact conversion factor (1 milliwatt = 0.001 watt). See the formula, worked examples, conversion table, history, and common uses.
Milliwatts to Watts converter
Converter
Power Converter
Convert watts, horsepower, refrigeration tons, BTU per hour, and engineering power units.
Context values
Some unit families need one extra value for a physically accurate result.
The watt is one joule per second.
Result = input x 0.001 / 1.
Power uses the watt as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Milliwatts to Watts
Milliwatt and Watt both describe power output, and the conversion is a routine part of comparing an engine or motor's spec sheet across countries that use different power units. Specifically: Milliwatt is 0.001 watt units, and the watt is one joule per second.
Formula
watts = milliwatts × 0.001
This factor comes from each unit's defined relationship to the category's base unit: 1 milliwatt equals 0.001 base units, and 1 watt equals 1 base unit, so dividing one by the other gives the direct milliwatt-to-watt factor of 0.001.
Simple example
1 mW × 0.001 = 0.001 W
1 milliwatt = 0.001 watts.
Real-world example
100 mW × 0.001 = 0.1 W
100 milliwatts = 0.1 watts.
Conversion table
| Milliwatt (mW) | Watt (W) |
|---|---|
| 1 mW | 0.001 W |
| 10 mW | 0.01 W |
| 100 mW | 0.1 W |
| 500 mW | 0.5 W |
| 1,000 mW | 1 W |
| 5,000 mW | 5 W |
Reverse conversion: Watt to Milliwatt
0.001 W × 1000 = 1 mW
0.001 watts = 1 milliwatt.
milliwatts = watts × 1000
For a page dedicated to this direction, see Watt to Milliwatt.
Understanding the Milliwatt (mW)
Milliwatt is 0.001 watt units.
Understanding the Watt
Watt (W) measures power. The watt is the SI derived unit of power: one joule of energy per second. It is classified as a SI derived unit.
Where it's used: Standard scientific and everyday power unit worldwide
Uses of the Watt today
- Electrical appliance power ratings worldwide
- Light bulb brightness-equivalent labeling
- Engine and motor power specifications (alongside horsepower)
History of the Watt
The watt is named after James Watt, whose improvements to the steam engine in the late 18th century were commercially pivotal; ironically, Watt himself used horsepower (a unit he helped popularize) to market his engines. The watt was formally adopted as a unit at the 1889 General Conference on Weights and Measures and became the SI derived unit of power in the 20th century.
Historical origin. Watt was not the invention of a single named person; it developed through the process described above.
Watt — sources
- BIPM SI Brochure — Coherent derived units — Defines the watt as the SI unit of power.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many watts are in 1 milliwatt?
1 milliwatt equals 0.001 watts, using the exact defined conversion factor rather than an estimate.
How do I convert milliwatt to watt?
Multiply the milliwatt value by 0.001. The converter above does this instantly to whatever precision you set.
How do I convert watt back to milliwatt?
Use the reverse factor: 1 watt equals 1,000 milliwatts. You can also use the swap control in the converter above to flip the direction instantly.
What is a milliwatt?
Milliwatt (mW) is a unit of power.
What is a watt?
Watt (W) measures power. The watt is the SI derived unit of power: one joule of energy per second. It is classified as a SI derived unit.
Is the milliwatt to watt conversion exact?
Yes. Both milliwatt and watt are defined by fixed standards rather than physical artifacts, so the factor of 0.001 used above is exact to as many digits as you choose to display.