dB to dBm Conversion Calculator

This tool converts from dB (deciBels) to dBm (deciBel-milliwatts)?

Enter the dB value and a reference dBm value into the calculator.

🔁 dBm to dB

Formula

dBm1 = dB + dBm2

Example

If

  • dBm2 = 30 dBm (or 1 Watt)
  • dB = 10 dB

then,

dBm1 = 40 dBm

In a practical context if the Noise power is 30 dBm and the Signal–to-noise ratio is 10 dB, then the Signal power is 40 dBm.

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Microwave Engineering