Enter Power
Formula
dBm = 10 log10(PmW)
The input is converted to milliwatts first because dBm is measured relative to 1 mW.
Worked Example
For 2 W, the power is 2000 mW:
dBm = 10 log10(2000) = 33.01 dBm
This is common when placing a transmitter's rated output into a link budget.
Use and Limits
Use this for transmitter output, amplifier power, signal-generator settings, and received-power comparisons. The result is valid for any positive power value.
Zero or negative watts cannot be converted to dBm. This calculator does not convert voltage to dBm because that also requires impedance.