This calculator converts between watts, dBm, volts and dBmV.
Select the Impedance then enter any one of the other parameters below and the rest will be calculated automatically
Most RF engineers will have memorised the following values:
dBm
mW
Notes
0
1
Exact by definition of dBm
3
2
3 dBm is actually 1.995 mW but that's near enough for most practical purposes
10
10
Exact
+3
X2
Adding 3 to the power in
dBm is the same as multiplying the power in Watts by two (actually 1.995
but that's near enough for most practical purposes)
+10
X10
Adding 10 the the power in dBm is exactly the same as multiplying the power in Watts by 10