dBm is decibel above a 1-milliwatt (mW) reference.

• A 1-Watt transmitter has an output of +30 dBm.
• A 10-Watt transmitter has an output of +40 dBm.
• A 25-Watt transmitter has an output of +44 dBm.

As can be seen, changing from dBW to dBm is simply a matter of adding or subtracting 30.

Portions of this text are provided by Brian Henderson and can also be found in his Program Operating Guide.

Calculate from and to other units ? Use the 'On-line RF calculator'.