How do I convert mW to watts or microwatts?

Formula : W = mW × 0.001 (or mW ÷ 1,000) µW = mW × 1,000 Examples : 1 mW = 0.001 W = 1,000 µW 100 mW = 0.1 W = 100,000 µW 1,000 mW = 1 W = 1,000,000 µW 10 mW = 0.01 W = 10,000 µW mW to Watts converter →

What is a safe laser power in mW?

Laser safety classes : Class 1 (< 0.4 mW): Inherently safe, cannot damage eye Class 2 (0.4-1 mW): Safe with blink reflex (~0.25 seconds) Class 3R (1-5 mW): Low risk with brief exposure, common laser pointers Class 3B (5-500 mW): Eye hazard, can cause injury Class 4 (> 500 mW): Severe eye and skin hazard, fire risk Recommendations : Safe for general use : ≤ 1 mW (Class 2) Laser pointers (legal) : < 5 mW in US (many countries limit to 1 mW) Avoid : > 5 mW for general use Industrial/medical : 10-10,000+ mW (requires safety training) Example : 5 mW green laser appears ~30x brighter than 5 mW red laser to human eye (wavelength sensitivity).

How much power does a typical Bluetooth device use?

Bluetooth power classes : Class 1 : 100 mW (20 dBm) - Range: ~100 meters Use case : Industrial, long-range applications Class 2 : 2.5 mW (4 dBm) - Range: ~10 meters Use case : Most consumer devices (headphones, mice) Class 3 : 1 mW (0 dBm) - Range: ~1 meter Use case : Very low power, proximity devices Bluetooth Low Energy (BLE) : 0.01-10 mW Advertising : 0.01-1 mW (intermittent) Connected : 1-10 mW Deep sleep : 0.001-0.01 mW Examples : Wireless earbuds : 2-10 mW (Class 2/3) Bluetooth speaker : 2.5-10 mW (Class 2) Fitness tracker : 0.1-5 mW (BLE)

What is dBm and how does it relate to mW?

dBm = Decibels relative to 1 milliwatt (logarithmic power scale) Formula : dBm = 10 × log₁₀(mW) Common conversions : dBm mW Description 0 1 Reference 3 2 Double 10 10 10x 20 100 100x 30 1,000 1W -10 0.1 1/10 -20 0.01 1/100 -30 0.001 1 µW Why use dBm? Large ranges easier to express: -50 dBm to +30 dBm vs 0.00001 mW to 1,000 mW Simplifies gain/loss calculations (add/subtract vs multiply/divide) Examples : Wi-Fi signal : -30 to -90 dBm (1,000 mW to 0.000001 mW) Cell tower : +43 dBm = 20,000 mW (20W) Bluetooth : 0 to +20 dBm (1-100 mW)

How long can a battery power a device using mW?

Formula : Battery life (hours) = (Battery capacity in mWh) ÷ (Device power in mW) Example calculations : CR2032 coin cell : 225 mAh @ 3V = 675 mWh LED (20 mW) : 675 ÷ 20 = 34 hours Bluetooth beacon (1 mW avg) : 675 ÷ 1 = 675 hours (~28 days) Watch (0.01 mW avg) : 675 ÷ 0.01 = 67,500 hours (~7.7 years) AA battery : 2,500 mAh @ 1.5V = 3,750 mWh LED flashlight (500 mW) : 3,750 ÷ 500 = 7.5 hours Remote control (5 mW avg) : 3,750 ÷ 5 = 750 hours (~31 days active) Smartphone battery : 15 Wh = 15,000 mWh Idle (200 mW) : 15,000 ÷ 200 = 75 hours (~3 days) Active use (2,000 mW) : 15,000 ÷ 2,000 = 7.5 hours

Milliwatt (mW) - Unit Information & Conversion

Symbol:mW

Plural:milliwatts

Category:Power

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What is a Milliwatt?

Milliwatt (mW) = 0.001 watts = 1/1000 W. Used for low-power electronics, lasers, wireless signals, medical devices. Laser pointer: 1-5 mW. Bluetooth: 1-100 mW. Hearing aid: 1 mW. Wi-Fi router: 30-100 mW per antenna.

History of the Milliwatt

SI metric prefix milli (10⁻³) applied to watt. Critical unit for telecommunications, consumer electronics, medical devices since mid-20th century. Standard for safety ratings of lasers and RF transmitters.

Quick Answer

What is a Milliwatt? A milliwatt (mW) = 0.001 watts = 1/1000 W. Used for small electronics, lasers, wireless signals. Laser pointer: 1-5 mW. Bluetooth device: 1-10 mW. LED indicator: 20-100 mW. 1,000 mW = 1 watt. Use our power converter for conversions.

Definition

1 mW = 0.001 W = 0.000001 kW = 1,000 µW (microwatts)

Common Uses

Lasers: Pointer lasers (1-5 mW), barcode scanners (1-10 mW). Wireless: Bluetooth (1-100 mW), Wi-Fi (10-1,000 mW), RFID tags. Medical: Hearing aids (1 mW), pacemakers (50-100 µW standby). Electronics: LEDs, sensors, low-power circuits.

Real-World Examples

Laser Devices

Class 2 laser pointer: 1 mW (safe, visible beam)
Class 3A laser pointer: 1-5 mW (bright, eye hazard)
Barcode scanner: 1-5 mW
Laser level: 1-5 mW
DVD laser (read): 5 mW
Blu-ray laser (read): 5 mW
CD burner laser (write): 100-300 mW

Wireless Communications

Bluetooth (Class 3): 1 mW (range: 1 meter)
Bluetooth (Class 2): 2.5 mW (range: 10 meters)
Bluetooth (Class 1): 100 mW (range: 100 meters)
Zigbee/Thread: 1-10 mW
Wi-Fi 2.4GHz: 30-100 mW (US limit: 1,000 mW)
Wi-Fi 5GHz: 30-200 mW
RFID passive tag: 0.1-1 mW
LoRa IoT: 10-100 mW

Medical Devices

Hearing aid: 1 mW typical
Pacemaker (active): 10-50 mW (pulses)
Pacemaker (standby): 0.05-0.1 mW (50-100 µW)
Insulin pump: 50-200 mW
Pulse oximeter: 5-20 mW (LED power)
Medical laser (therapy): 1-1,000 mW

Consumer Electronics

LED indicator (small): 5-20 mW
LED indicator (bright): 20-100 mW
Watch backlight: 1-5 mW
Calculator solar cell: 1-10 mW
Remote control IR LED: 10-100 mW (peak)
Fitness tracker: 5-50 mW
Smartwatch (idle): 20-100 mW

Radio Transmitters

Walkie-talkie (FRS): 500 mW
CB radio: 4,000 mW (4W)
Amateur radio (handheld): 5,000 mW (5W)
Garage door opener: 10-100 mW
Wireless headphones: 1-10 mW
Wireless mouse: 0.5-5 mW

Milliwatt Conversion Formulas

To Watt:

1 mW = 0.001 W

Example: 5 milliwatts = 0.005 watts

To Kilowatt:

1 mW = 0.000001 kW

Example: 5 milliwatts = 0.000005 kilowatts

To Megawatt:

1 mW = 1.0000e-9 MW

Example: 5 milliwatts = 5.0000e-9 megawatts

To Gigawatt:

1 mW = 1.0000e-12 GW

Example: 5 milliwatts = 5.0000e-12 gigawatts

To Horsepower:

1 mW = 0.000001 hp

Example: 5 milliwatts = 0.000007 horsepower

To Metric Horsepower:

1 mW = 0.000001 PS

Example: 5 milliwatts = 0.000007 PS

To Electric Horsepower:

1 mW = 0.000001 hp(E)

Example: 5 milliwatts = 0.000007 hp(E)

To BTU per Hour:

1 mW = 0.003412 BTU/h

Example: 5 milliwatts = 0.017061 BTU/h

To BTU per Minute:

1 mW = 0.000057 BTU/min

Example: 5 milliwatts = 0.000284 BTU/min

To BTU per Second:

1 mW = 9.4782e-7 BTU/s

Example: 5 milliwatts = 0.000005 BTU/s

To Foot-pound per Second:

1 mW = 0.000738 ft⋅lb/s

Example: 5 milliwatts = 0.003688 ft⋅lb/s

To Foot-pound per Minute:

1 mW = 0.044254 ft⋅lb/min

Example: 5 milliwatts = 0.221269 ft⋅lb/min

To Calorie per Second:

1 mW = 0.000239 cal/s

Example: 5 milliwatts = 0.001195 cal/s

To Kilocalorie per Hour:

1 mW = 0.00086 kcal/h

Example: 5 milliwatts = 0.004302 kcal/h

To Ton of Refrigeration:

1 mW = 2.8435e-7 TR

Example: 5 milliwatts = 0.000001 TR

To Erg per Second:

1 mW = 10000 erg/s

Example: 5 milliwatts = 50000 erg/s

To Joule per Second:

1 mW = 0.001 J/s

Example: 5 milliwatts = 0.005 J/s

Frequently Asked Questions

Formula:

W = mW × 0.001 (or mW ÷ 1,000)
µW = mW × 1,000 Examples:
1 mW = 0.001 W = 1,000 µW
100 mW = 0.1 W = 100,000 µW
1,000 mW = 1 W = 1,000,000 µW
10 mW = 0.01 W = 10,000 µW mW to Watts converter →

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