dBm is a unit of power relative to 1 milliwatt. 0 dBm = 1 mW. Positive dBm values indicate power above 1 mW (e.g. 10 dBm = 10 mW). Negative dBm values indicate power below 1 mW (e.g. −30 dBm = 0.001 mW = 1 µW). dBm is used in RF engineering for transmit powers, received signal levels, and sensitivity thresholds.

dBm to mW Calculator

Q: How do I convert dBm to milliwatts?

Use the formula: mW = 10^(dBm / 10). For example: 20 dBm = 10^(20/10) = 10^2 = 100 mW. Or: −10 dBm = 10^(−10/10) = 10^−1 = 0.1 mW.

Q: What is a typical WiFi transmit power in dBm?

Consumer WiFi routers typically transmit at 15–23 dBm (32–200 mW) per radio. Enterprise access points can transmit at up to 23–27 dBm depending on the country regulatory limits. Received signal strength at a client is typically −50 to −80 dBm.

Convert wireless power between dBm and milliwatts (mW) in either direction. Used for transmit power, received signal strength, antenna gain, and receiver sensitivity in RF and WiFi engineering.

dBm ↔ mW Converter

Conversion Direction

Power Level (dBm)

Power Level (mW)

Conversion Result

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Milliwatts (mW)

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dBm

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Watts (W)

Formulas

dBm to mW: mW = 10 ^ (dBm ÷ 10) mW to dBm: dBm = 10 × log₁₀(mW) mW to Watts: W = mW ÷ 1000

Common dBm Reference Table

dBm	mW	W	Typical Use
30 dBm	1,000 mW	1 W	Max EIRP in many regions (2.4 GHz)
27 dBm	500 mW	0.5 W	High-power enterprise AP transmit
23 dBm	200 mW	0.2 W	Typical enterprise AP transmit power
20 dBm	100 mW	0.1 W	Consumer WiFi router transmit power
17 dBm	50 mW	0.05 W	Low-power AP or indoor coverage
10 dBm	10 mW	0.01 W	Bluetooth transmit power
0 dBm	1 mW	0.001 W	Reference level (0 dBm = 1 mW)
−30 dBm	0.001 mW	1 µW	Excellent WiFi RSSI at client
−50 dBm	0.0001 mW	0.1 µW	Good WiFi signal at 20–30 m
−70 dBm	0.0000001 mW	0.1 nW	Weak/acceptable WiFi signal
−85 dBm	—	—	Minimum usable WiFi signal
−95 dBm	—	—	Typical WiFi noise floor

Why dBm Uses a Logarithmic Scale

Wireless signal power spans many orders of magnitude — from 1 W transmit power down to 0.000000001 W at a distant receiver. Expressing this as milliwatts gives unwieldy numbers. The logarithmic dBm scale compresses this range into manageable numbers: 30 dBm down to −90 dBm is much easier to work with than 1,000 mW down to 0.000001 mW.

Every +3 dBm approximately doubles the power (3 dB ≈ 2×).
Every +10 dBm increases power by exactly 10× (10 dB = 10×).
Adding gains and losses in dB is just addition/subtraction — no multiplication needed.

Frequently Asked Questions

What is dBm?

dBm is power measured relative to 1 milliwatt using a decibel scale. 0 dBm = 1 mW. 10 dBm = 10 mW. 20 dBm = 100 mW. Negative values represent power less than 1 mW: −10 dBm = 0.1 mW, −30 dBm = 0.001 mW. It is the standard unit for RF power levels.

How do I convert dBm to milliwatts?

mW = 10^(dBm ÷ 10). Examples: 0 dBm = 10^0 = 1 mW. 10 dBm = 10^1 = 10 mW. 20 dBm = 10^2 = 100 mW. −10 dBm = 10^−1 = 0.1 mW. −20 dBm = 10^−2 = 0.01 mW.

What is a typical WiFi transmit power in dBm?

Consumer home routers: 15–20 dBm (32–100 mW). Enterprise APs: 20–27 dBm. Received signal (RSSI) at a laptop 10 m away: −40 to −55 dBm. Minimum usable RSSI for WiFi: around −85 to −90 dBm. Most WiFi networks work well at −50 to −70 dBm RSSI.