Convert Milliwatts (mW) to Watts (W)

Q: How many milliwatts in a watt?

Exactly 1,000 milliwatts. This is an exact SI definition — "milli-" means one thousandth.

Q: What is 1 mW in dBm?

0 dBm. The dBm scale is defined relative to 1 milliwatt: 0 dBm = 1 mW. Each +3 dBm doubles the power; each +10 dBm multiplies by 10.

1 milliwatt equals 0.001 watts.

Formula: W = mW × 0.001

Milliwatt to Watt Converter

What Is a Milliwatt?

The milliwatt (mW) is an SI unit of power equal to one thousandth of a watt (0.001 W or 10⁻³ W). It is used for low-power applications: WiFi and Bluetooth transmitter power, laser classification, LED indicators, sensor power consumption, and RF signal strength.

What Is a Watt?

The watt (W) is the SI base unit of power, equal to one joule per second. Named after James Watt, it measures the rate of energy transfer. Consumer electronics and appliances are typically rated in watts or kilowatts.

Milliwatts to Watts Formula

The conversion is exact by SI definition:

watts = milliwatts ÷ 1,000

The "milli-" prefix means exactly one thousandth. No rounding needed.

Worked Example

Convert 250 mW (typical WiFi router transmit power) to watts:

Divide: 250 ÷ 1,000 = 0.25 W

Common Milliwatts to Watts Conversions

Milliwatts	Watts	dBm	Context
0.001 mW	0.000001 W	−30 dBm	Weak WiFi signal at receiver
0.1 mW	0.0001 W	−10 dBm	Bluetooth Low Energy
1 mW	0.001 W	0 dBm	Reference power (0 dBm definition)
2.5 mW	0.0025 W	4 dBm	Bluetooth Classic (Class 2)
10 mW	0.01 W	10 dBm	WiFi client device transmit
100 mW	0.1 W	20 dBm	Bluetooth Class 1 / FRS radio
250 mW	0.25 W	24 dBm	WiFi router (typical 2.4 GHz)
500 mW	0.5 W	27 dBm	High-power WiFi / amateur radio
1,000 mW	1 W	30 dBm	1 watt — FRS/GMRS radio (max)

Milliwatts and dBm

In RF engineering, power is often expressed in dBm (decibels relative to 1 milliwatt). The relationship is logarithmic: dBm = 10 × log₁₀(mW). Key reference points: 0 dBm = 1 mW, 10 dBm = 10 mW, 20 dBm = 100 mW, 30 dBm = 1,000 mW = 1 W. Every 3 dBm increase doubles the power.

When You Need This Conversion

WiFi and networking: Router specs list transmit power in mW or dBm. A 250 mW (24 dBm) router has 2.5× the range potential of a 100 mW (20 dBm) unit.
Laser safety: Laser class limits are in mW. Class 1 lasers are ≤0.39 mW; Class 3B ranges from 5 to 500 mW = 0.005 to 0.5 W.
IoT and sensors: Battery-powered sensors consume 0.01-10 mW. A 10 mW sensor on a 3,000 mWh battery lasts 300 hours.

Frequently Asked Questions

How many milliwatts in a watt?

Exactly 1,000 milliwatts. This is an exact SI definition — "milli-" means one thousandth.

What is 1 mW in dBm?

0 dBm. The dBm scale is defined relative to 1 milliwatt: 0 dBm = 1 mW. Each +3 dBm doubles the power; each +10 dBm multiplies by 10.

How do I convert dBm to milliwatts?

mW = 10^(dBm/10). Example: 20 dBm = 10^(20/10) = 10² = 100 mW. Quick table: 0 dBm = 1 mW, 10 dBm = 10 mW, 20 dBm = 100 mW, 30 dBm = 1,000 mW.

How do I convert watts to milliwatts?

Multiply by 1,000. Example: 0.5 W × 1,000 = 500 mW.

Common Milliwatt to Watt Conversions

Milliwatt to Watt (Part 1)

Milliwatt	Watt	Actions
1 milliwatt	0.001 watts
10 milliwatts	0.01 watts
100 milliwatts	0.1 watts

Milliwatt to Watt (Part 2)

Milliwatt	Watt	Actions
500 milliwatts	12 watts
1000 milliwatts	1 watt

Milliwatts to watts Conversion Table

Reference table with common milliwatts to watts conversions. All values calculated with high precision.

Milliwatts to Watts Table
0.1 to 500

Milliwatts	Watts	Actions
0.1 mW	0.0001 W
14 mW	0.00025 W
12 mW	0.0005 W
1 mW	0.001 W
2 12 mW	0.0025 W
5 mW	0.005 W
10 mW	0.01 W
25 mW	0.025 W
50 mW	0.05 W
100 mW	0.1 W
250 mW	14 W
500 mW	12 W

Milliwatts to Watts Table
1000 to 1 × 10⁸

Milliwatts	Watts	Actions
1000 mW	1 W
2500 mW	2 12 W
5000 mW	5 W
10000 mW	10 W
25000 mW	25 W
50000 mW	50 W
100000 mW	100 W
250000 mW	250 W
500000 mW	500 W
1000000 mW	1000 W
2500000 mW	2500 W
5000000 mW	5000 W
10000000 mW	10000 W
2.5 × 10⁷ mW	25000 W
5 × 10⁷ mW	50000 W
1 × 10⁸ mW	100000 W

Watts to Milliwatts Table
0.0001 to 12

Watts	Milliwatts	Actions
0.0001 W	0.1 mW
0.00025 W	14 mW
0.0005 W	12 mW
0.001 W	1 mW
0.0025 W	2 12 mW
0.005 W	5 mW
0.01 W	10 mW
0.025 W	25 mW
0.05 W	50 mW
0.1 W	100 mW
14 W	250 mW
12 W	500 mW

Watts to Milliwatts Table
1 to 100000

Watts	Milliwatts	Actions
1 W	1000 mW
2 12 W	2500 mW
5 W	5000 mW
10 W	10000 mW
25 W	25000 mW
50 W	50000 mW
100 W	100000 mW
250 W	250000 mW
500 W	500000 mW
1000 W	1000000 mW
2500 W	2500000 mW
5000 W	5000000 mW
10000 W	10000000 mW
25000 W	2.5 × 10⁷ mW
50000 W	5 × 10⁷ mW
100000 W	1 × 10⁸ mW

Looking for the reverse? Convert Watt to Milliwatt

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Conversion factors verified against NIST, BIPM, ISO 80000-4 Based on SI base units (W = J/s, BIPM). Last reviewed: April 2026

By Adilson Fernandes

Reviewed by Tiago Fernandes

All unit conversions on CoolConversion use conversion factors defined or documented by internationally recognised standards bodies (such as ISO and NIST), including both SI and non-SI units.