I am trying to follow an example formula in my text on how to convert dBm to dBw. The formula given is +10dBm=10log P^2/0.001 log^-1(1)=P^2/0.001 => 10 = P^2/0.001 P^2=0.001 W dBW=10log 0.001W/1W=-20 dBw I believe 10 dBm to be a bad example. I don't fully understand how to do this formula. I have found two ways to put this in my calculator and get the correct answer but if I substitute 10 dBm for 20 dBm I don't get the correct answer, therefore I am doing it wrong somewhere. How did the text get log^-1 out of log when it moved it to the other side of the equation? Can someone explain to me how to do this conversion.