dBm to Watts Converter
Convert between dBm, watts, and dBW, and find the RMS voltage into a load impedance. Leave power or dBm blank to solve for it.
Solved value–
Power–
Power (dBm)–
Power (dBW)–
RMS voltage into load–
dBm, dBW, and watts
dBm expresses power on a logarithmic scale referenced to 1 milliwatt, which makes the huge range of RF and audio powers easy to handle and lets gains and losses simply add up along a signal chain.
dBm = 10 · log₁₀(P / 1 mW)
P = 1 mW × 10^(dBm / 10)
dBW is the same idea referenced to 1 watt, so dBW = dBm − 30. Into a resistive load R, the RMS voltage is √(P · R) — for example 0 dBm (1 mW) into 50 Ω is about 224 mV.
Related
For voltage or power ratios in decibels (gain), see thedecibel converter; for amplifier gain, the op-amp gain calculator.