What is microwatt?

A microwatt is a unit of power equal to one millionth of a watt. It is used in ultra-low-power electronics, energy harvesting systems, biosensors, and precision scientific instrumentation.

Real-world uses

Microwatts measure the power of radio frequency (RF) signals received by antennas, ultra-low-power IoT sensors, cardiac pacemaker power consumption, and energy-harvesting devices. Satellite receivers may work with signals in the nanowatt to microwatt range. Wearable health monitors often operate at a few microwatts.

History

Microwatts became a meaningful engineering unit as semiconductor miniaturisation through the 1970s–2000s enabled ultra-low-power circuit design. The proliferation of wireless sensors, implantable medical devices, and battery-free energy harvesting systems in the early 21st century made µW-level power budgeting essential.

Common mistakes

Confusing microwatts (µW) with milliwatts (mW)—a difference of 1,000×. In RF engineering, power is often expressed in dBm (decibels relative to 1 mW), which requires knowing that 0 dBm = 1 mW = 1,000 µW, and negative dBm values correspond to sub-milliwatt levels.

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.

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 microwatt to milliwatt is useful in the power domain when comparing values across different measurement standards or applying formulas that require a specific unit.

Worked examples

1 microwatt = 0.001 milliwatt

1 milliwatt = 0.001 watt

How to convert microwatt to milliwatt

To convert microwatt to milliwatt, multiply the value by 0.001.

To convert milliwatt back to microwatt, multiply by 1,000.

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.

Quick reference: microwatt to milliwatt

microwatt	milliwatt
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

	microwatt	milliwatt
LED light bulb	10,000,000 microwatt	10,000 milliwatt
Desktop computer	300,000,000 microwatt	300,000 milliwatt
Microwave oven	1.000000e+09 microwatt	1,000,000 milliwatt
Small car engine	7.500000e+10 microwatt	75,000,000 milliwatt
Wind turbine (large)	3.000000e+12 microwatt	3.000000e+09 milliwatt

Available Power units

More microwatt conversions

Assumption: horsepower values use mechanical horsepower.