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.

What is megawatt?

A megawatt is a unit of power equal to one million watts. It is used to rate the output of power plants, large industrial facilities, and grid-scale renewable energy installations.

Real-world uses

Megawatts describe the output of power plants, wind turbines (typically 2–15 MW each), and large solar farms. A modern natural gas peaker plant might produce 50–500 MW. Data centres may have power demands of tens to hundreds of MW. Grid operators manage supply and demand in MW.

History

As electrical grids grew through the 20th century, the megawatt became the standard unit for power station output and grid management. It enables comparisons across coal, gas, nuclear, and renewable generation sources on a common scale.

Common mistakes

Confusing MW (power) with MWh (energy). A 100 MW power plant running for 10 hours generates 1,000 MWh (1 GWh) of energy. Also, not distinguishing between MW of capacity (nameplate) and MW of actual output (which varies for renewables).

When is this conversion used?

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

Worked examples

1 milliwatt = 1.000000e-09 megawatt

1 megawatt = 1,000,000 watt

How to convert milliwatt to megawatt

To convert milliwatt to megawatt, multiply the value by 1.000000e-09.

To convert megawatt back to milliwatt, multiply by 999,999,999.99999988.

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: milliwatt to megawatt

Common values

Available Power units

• watt conversions
• kilowatt conversions
• horsepower (mechanical) conversions
• megawatt conversions
• gigawatt conversions
• milliwatt conversions
• microwatt conversions
• BTU per hour conversions
• kilocalorie per hour conversions
• ton of refrigeration conversions

More milliwatt conversions

• Convert milliwatt to watt
• Convert milliwatt to kilowatt
• Convert milliwatt to horsepower (mechanical)
• Convert milliwatt to megawatt
• Convert milliwatt to gigawatt
• Convert milliwatt to microwatt
• Convert milliwatt to BTU per hour
• Convert milliwatt to kilocalorie per hour
• Convert milliwatt to ton of refrigeration

Assumption: horsepower values use mechanical horsepower.