What is dBm?
dBm (decibel-milliwatts) is a logarithmic unit used to express power levels relative to 1 milliwatt. It is widely used in radio frequency (RF), WiFi, cellular, and fiber-optic signal measurements because it compresses a huge range of power values into a compact, easy-to-compare scale.
How the Conversion Works
The standard formula converts dBm to milliwatts using base-10 exponentiation: P(mW) = 10^(dBm/10). This calculator applies that formula, then divides by 1000 to also show the result in watts and kilowatts.
- 0 dBm = 1 mW
- 10 dBm = 10 mW
- 30 dBm = 1 W
This tool is intended for general engineering and educational reference; always double-check critical RF calculations with calibrated test equipment.
Last reviewed August 2026