Health How many watts are in a dB? How many DB is 30 watts? dBW scale Watts --------- ------- 0 dBW 1 watt -10 dBW 0.1 W -30 dBW 0.001 W -30 dBW 0 dBm How much power is 10dbm? Unit conversions A power level of 0 dBm corresponds to a power of 1 milliwatt. A 10 dB increase in level is equivalent to a 10-fold increase in power. Therefore, a 20 dB increase in level is equivalent to a 100-fold increase in power.