Using the calculations below you can convert dBm to watts and milliWatts. dBm is used to express an absolute value of power relative to a milliwatt.

dBm	=	Unit to express relative difference in power or intensity.
mW	=	Unit of power equal to 1/1000 (10-3) of a watt.
W	=	Unit of power equal to 1 joule per sec.

Calculate milliwatts to dBm: dBm = (10Log10())

Calculate dBm to Watts: W = 10((-30)/10) mW = 10(/10)