RF Power dBm Calculator
Convert between watts and dBm for RF power measurements, and calculate voltage into a given impedance.
mW
Ω
Power (dBm)
20.00 dBm
Power (W)0.100000 W
RMS Voltage2,236.1 mV
Power (dBm) vs Power
RF Power in dBm
Formulas
dBm = 10 x log10(P_mW)
V_rms = sqrt(P x Z)
dBm is decibels relative to 1 milliwatt. Common values: 0 dBm = 1 mW, 10 dBm = 10 mW, 20 dBm = 100 mW, 30 dBm = 1 W.
Example Calculation
100 mW transmitter into 50 ohm system.
- 01dBm = 10 x log10(100) = 20 dBm
- 02Power = 100 / 1000 = 0.1 W
- 03V_rms = sqrt(0.1 x 50) x 1000 = 2236 mV
Frequently Asked Questions
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