What this converter does
This converter turns a dBm power level into watts and back. Because dBm is logarithmic, the relationship is exponential — every 10 dB is a ten-times change in power, and 3 dB roughly doubles it. Type a dBm value and read the power instantly.
dBm is referenced to one milliwatt, so 0 dBm = 1 mW and 30 dBm = 1 W. It is the standard way to state transmitter output and receiver sensitivity in RF and networking.
The units it covers
These are two ways to state the same RF power — a logarithmic level (dBm) and linear power (watts), tied by a base-10 relationship.
View all units & their values
| Unit | Symbol | Value | Mainly used |
|---|---|---|---|
| Decibel-milliwatt | dBm | log | RF & signal power level |
| Watt | W | linear | Actual power |
| Milliwatt | mW | linear | dBm reference (0 dBm = 1 mW) |
The formula
dBm is ten times the base-10 log of power in milliwatts, so the link to watts is exponential, not a fixed factor:
W = 10^((dBm − 30) ÷ 10)Where:
- dBm = power level referenced to 1 milliwatt
- W = power in watts
- 30 = the mW→W offset (0 dBm = 1 mW = 0.001 W)
Worked example
Convert 30 dBm to watts.
W = 10^((dBm − 30) ÷ 10)10^((30 − 30)/10) = 1 WSo 30 dBm is exactly 1 watt — a common Wi-Fi/transmit reference.
The units in this example
A logarithmic power level referenced to 1 mW. Used for RF transmit power and receiver sensitivity.
- 0 dBm = 1 mW
- 30 dBm = 1 W
- +3 dBm ≈ ×2 power
- +10 dBm = ×10 power
Linear power. One watt equals 30 dBm; a milliwatt equals 0 dBm.
- 1 W = 30 dBm
- 0.001 W = 0 dBm
- 100 W = 50 dBm
- 0.5 W ≈ 27 dBm