Convert Milliwatts to Watts
1 milliwatt (mW) equals 0.001 watts (W).
1 mW = 0.001 W
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk milliwatt to watt converter to paste a column from Excel.
How to Convert Milliwatt to Watt
- 1 mW = 0.001 W
- 1 W = 1000 mW
- Example: convert 15 mW to W: 15 mW = 15 × 0.001 W = 0.015 W
Formula
W = mW ÷ 1000
Derivation from SI units:
- 1 mW = 10⁻³ W
- 1 W = 1 J/s = 1 kg·m²·s⁻³
Both units are defined exactly, so the factor is exact. Milliwatt definition: milliwatt; Watt definition: watt.
Worked examples
- A reading of 10 mW converts to 0.01 W.
10 mW × 0.001 = 0.01 W - A value of 200 mW is 0.2 W.
200 mW × 0.001 = 0.2 W
Milliwatt to Watt conversion table
| Milliwatts (mW) | Watts (W) |
|---|---|
| 0.1 mW | 0.0001 W |
| 1 mW | 0.001 W |
| 5 mW | 0.005 W |
| 10 mW | 0.01 W |
| 50 mW | 0.05 W |
| 100 mW | 0.1 W |
| 200 mW | 0.2 W |
| 500 mW | 0.5 W |
| 1000 mW | 1 W |
Where it's used
Milliwatts are used for laser pointer and diode output, while watts appear in electrical appliance ratings. Both measure power (energy per unit time), so the conversion is a fixed factor.
Milliwatt to other power units
| Conversion | 1 mW equals |
|---|---|
| milliwatt to watt | 0.001 W |
| milliwatt to kilowatt | 0.000001 kW |
| milliwatt to megawatt | 1 × 10⁻⁹ MW |
| milliwatt to horsepower | 0.00000134102209 hp |
| milliwatt to metric horsepower | 0.000001359621617 PS |
| milliwatt to BTU per hour | 0.003412141633 BTU/h |
| milliwatt to refrigeration ton | 2.843451361 × 10⁻⁷ TR |
| milliwatt to kilocalorie per hour | 0.0008598452279 kcal/h |
| milliwatt to foot-pound per second | 0.0007375621493 ft·lbf/s |
Frequently asked questions
How many watts are in 1 milliwatt?
1 mW = 0.001 W.
How do I convert milliwatts to watts?
Multiply the value in mW by 0.001, or divide it by 1000. For example, 15 mW × 0.001 = 0.015 W.
Is the mW to W conversion exact?
Yes. Both units are defined exactly, and 1 mW is exactly 0.001 W.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 7, SI prefixes.
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4, coherent derived units with special names.
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Milliwatts to Watts. Retrieved October 17, 2026, from https://scientificconverters.com/power/milliwatts-to-watts/
IEEE
Scientific Converters, "Convert Milliwatts to Watts," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/power/milliwatts-to-watts/