milliwatt (mW)
1 milliwatt = 0.001 watts
What is milliwatt?
A milliwatt is a unit of power equal to one thousandth of a watt. It is used in low-power electronics, wireless communication systems, laser specifications, and medical device power ratings.
Notes: Small-scale power
Real-world uses
Milliwatts measure the power of laser pointers (Class 1: <1 mW; Class 3B: up to 500 mW), Bluetooth radios (typically 1–100 mW), Wi-Fi transmitters, and fibre optic signals. They are used in optical communications, consumer electronics, and medical laser specifications.
History
Milliwatts became relevant as the miniaturisation era brought small electrical and optical devices into widespread use from the mid-20th century. Consumer electronics, telecommunications, and biomedical equipment all required power specifications at this sub-watt scale.
Common mistakes
Confusing milliwatts (mW) with microwatts (µW)—1 mW = 1,000 µW. Also, assuming all laser pointers operate at the same power level; safety regulations classify lasers by output power in mW, and even small increases can be hazardous to the eyes.
When is this conversion used?
Converting milliwatt to watt is useful in the power domain when comparing values across different measurement standards or applying formulas that require a specific unit.
How to convert milliwatt to watt
To convert milliwatt to watt, multiply the value by 0.001.
Conversion formula (from base unit)
x * 0.001
Measurement standards
The watt is the SI derived unit of power, defined as one joule per second (kg·m²/s³). Horsepower remains in widespread informal use, particularly in the automotive industry, but has no single universal definition across regions.
Did you know?
The human body at rest produces about 80 watts of power — roughly enough to keep an incandescent light bulb glowing. During intense exercise, a trained cyclist can sustain over 400 watts, and elite sprinters briefly exceed 2,000 watts.
| milliwatts | watts |
|---|---|
| 0.1 | 0.0001 |
| 0.5 | 0.0005 |
| 1 | 0.001 |
| 2 | 0.002 |
| 5 | 0.005 |
| 10 | 0.01 |
| 25 | 0.025 |
| 50 | 0.05 |
| 100 | 0.1 |
| 250 | 0.25 |
| 500 | 0.5 |
| 1,000 | 1 |
Common values
| milliwatts | watts | |
|---|---|---|
| LED light bulb | 10,000 milliwatts | 10 watts |
| Desktop computer | 300,000 milliwatts | 300 watts |
| Microwave oven | 1,000,000 milliwatts | 1,000 watts |
| Small car engine | 75,000,000 milliwatts | 75,000 watts |
| Wind turbine (large) | 3.000000e+09 milliwatts | 3,000,000 watts |
Full milliwatt conversion table
| Unit | Value | Factor |
|---|---|---|
| watt | 1 mW = 0.001 W | × 0.001 |
| kilowatt | 1 mW = 0.000001 kW | × 0.000001 |
| horsepower (mechanical) | 1 mW = 0.00000134 hp | × 0.00000134 |
| megawatt | 1 mW = 1.000000e-09 MW | × 1.000000e-09 |
| gigawatt | 1 mW = 1.000000e-12 GW | × 1.000000e-12 |
| microwatt | 1 mW = 1,000 µW | × 1,000 |
| BTU per hour | 1 mW = 0.00341214 BTU/h | × 0.00341214 |
| kilocalorie per hour | 1 mW = 0.00085985 kcal/h | × 0.00085985 |
| ton of refrigeration | 1 mW = 2.843451e-07 TR | × 2.843451e-07 |