dBm ↔ mW Converter

Convert between power units

Power units

Power (dBm)

Power (mW)

Power (W)

Power (nW)

Power conversion reference

Formula: P(dBm) = 10 × log₁₀(P(mW))
0 dBm = 1 mW = 0.001 W
30 dBm = 1000 mW = 1 W
-30 dBm = 0.001 mW = 1000 nW = 1 µW
-70 dBm = 0.0000001 mW = 0.1 nW

Common RF power levels

WiFi Router~20 dBm (100 mW)

Cell Phone~23 dBm (200 mW)

Bluetooth~0 dBm (1 mW)

WiFi Receiver~-70 dBm (0.1 nW)

GPS Signal~-130 dBm (0.1 fW)

FM Radio~50 dBm (100 W)

Microwave Link~36 dBm (4 W)

What dBm means

dBm is power on a logarithmic scale, measured against one milliwatt. 0 dBm is 1 mW; every 10 dB more is ten times the power, every 3 dB about twice. That turns the huge range of radio and optical power into small numbers, and gains and losses in dB simply add to a level in dBm.

P(dBm) = 10 · log₁₀(P / 1 mW)
P(mW) = 10^{P(dBm) / 10}

Examples

20 dBm is 100 mW, 30 dBm is 1 W, and −30 dBm is 1 µW, or 1000 nW. Very small powers appear as powers of ten: −100 dBm is 1.000e-10 mW, a tenth of a picowatt.