Watts <> dBm <> Volts Converter

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This calculator converts between watts, dBm, volts and dBmV.

Select the Impedance then enter any one of the other parameters below and the rest will be calculated automatically

Impedance (Ω): Common in RF and Microwave Systems
Common in TV and Video Systems
Common in Audio Systems
Custom Value
milli Watts (mW):
Watts (W):
VPeak: Assuming a sine wave
VP-P: Assuming a sine wave
dBmV: dB relative to 1mV RMS. Often used in the cable TV industry and only valid in 75Ω systems

Most RF engineers will have memorised the following values:

0 1Exact by definition of dBm
3 23 dBm is actually 1.995 mW but that's near enough for most practical purposes
10 10Exact
+3 ×2Adding 3 to the power in dBm is the same as multiplying the power in Watts by two (actually 1.995 but that's near enough for most practical purposes)
+10×10Adding 10 the the power in dBm is exactly the same as multiplying the power in Watts by 10

Whilst I try to keep the information on this site accurate, I'm only human and I do occasionally make mistakes. I therefore advise you to check any information before using it for anything important. If you do find any errors, please let me know so that I can correct them.

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This page was last changed on: 20 November 2020.

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