dBm to Volts to Watts Conversion
Enter power level \(P(\mathrm{dBm})\) and impedance \(Z\) to compute \(V_{\mathrm{RMS}}\) and \(P(\mathrm{W})\). (Example: \(P=100\,\mathrm{dBm}\), \(Z=50\,\Omega\) → \(V_{\mathrm{RMS}}\approx 22360.7\,\mathrm{V}\))
dBm is defined as power ratio in decibel (dB) referenced to one milliwatt (mW). It is an abbreviation for dB with respect to 1 mW and the “m” in dBm stands for milliwatt.
Calculations
Inputs: P(dBm), Z(Ω)| Power level | — | P(dBm) ref 1 mW |
|---|---|---|
| Voltage | — | V(RMS) |
| Watt | — | P(watts) |
| Impedance | — | Z Ω |
Formulas
\[
P(\mathrm{W}) = 10^{\frac{P(\mathrm{dBm}) - 30}{10}}
\]
\[
V_{\mathrm{RMS}}(\mathrm{V}) = \sqrt{\frac{Z}{1000}}\;10^{\frac{P(\mathrm{dBm})}{20}}
\]
\[
P(\mathrm{dBm}) = 10\log_{10}\!\big(P(\mathrm{W})\big) + 30
\]
\[
P(\mathrm{dBm}) = 10\log_{10}\!\left(\frac{V_{\mathrm{RMS}}^{2}\cdot 1000}{Z}\right)
\]
* Ensure \(Z>0\). Very large dBm values can produce very large Watts/Volts results.