 Watts <> dBm conversion

 
The logarithmic power units of dBm are defined such that 1 W = 0 dBm, and each tenfold rise in W gives a ten unit rise in dBm.
 
In high frequency systems, power is often given in the logarithmic units of dBm, in order to allow a convenient span over a many orders of magnitude with a small range of numbers. Fill in either the power in W or the power in dBm in the blue box, and the calc will provide the equal dBm or W value in the orange box.  