Use this next calculator to convert from dBW (deciBel Watt) to dBm (deciBel milliwatt).
Conversion Formula
Since 1 watt (W) is equal to 1000 milliwatts (mW), the relationship between dBW and dBm is as follows:
PdBm = PdBW + 30
Explanation
- dBW is referenced to 1 watt.
- dBm is referenced to 1 milliwatt.
- Since 1 W = 1000 mW, and 10*Log10(1000)=30, you add 30 to the dBW value to convert it to dBm.
Example Calculations
Convert 5 dBW to dBm
PdBm= 5 dBW + 30 = 35 dBm
Convert -10 dBW to dBm
PdBm= −10 dBW + 30 = 20 dBm