The dBmV to dBm calculator allows you to convert the power expressed in dBmV into dBm taking into account the characteristic impedance of the system.
This tool is useful for RF engineers and technicians to check signal levels in cable networks or transmission systems.
Formula used
dBm = dBmV – 30 – 10 × log10(Zo)
Or :
dBmV = signal level in dBmV
Zo = characteristic impedance of the circuit (Ω)
dBm = power in dBm
Explanation
The conversion takes into account the reference difference between dBmV and dBm as well as the system impedance.
Subtracting 30 adjusts the scale from millivolts to milliwatts, and the -10 × log10(Zo) part corrects for impedance.
This formula allows power levels in different RF systems to be compared and analyzed consistently.
Calculation example
For a 10 dBmV signal with impedance Zo = 75 Ω :
dBm = 10 – 30 – 10 × log10(75) ≈ -38.75 dBm
Benefits and Use
- Fast and accurate conversion between dBmV and dBm for RF analysis.
- Useful for sizing and testing cable networks or transmission systems.
- Helps compare signal levels in different equipment and configurations.
- Helps ensure signals stay within expected ranges to avoid loss or distortion.