How to convert dBm to dBW
dBW = dBm − 30Both are decibel scales with different reference levels, so they differ by a constant.
Worked examples
- −30 dBm−30 dBm → −60 dBW
- −3 dBm−3 dBm → −33 dBW
- 6 dBm6 dBm → −24 dBW
- 30 dBm30 dBm → 0 dBW
- 50 dBm50 dBm → 20 dBW
DBm to dBW conversion table
Values are calculated by the conversion engine using the full formula and rounded to 8 significant figures.
| DBm (dBm) | DBW (dBW) |
|---|---|
| −60 dBm | −90 dBW |
| −40 dBm | −70 dBW |
| −30 dBm | −60 dBW |
| −20 dBm | −50 dBW |
| −10 dBm | −40 dBW |
| −3 dBm | −33 dBW |
| 0 dBm | −30 dBW |
| 3 dBm | −27 dBW |
| 6 dBm | −24 dBW |
| 10 dBm | −20 dBW |
| DBm (dBm) | DBW (dBW) |
|---|---|
| 13 dBm | −17 dBW |
| 20 dBm | −10 dBW |
| 23 dBm | −7 dBW |
| 27 dBm | −3 dBW |
| 30 dBm | 0 dBW |
| 33 dBm | 3 dBW |
| 37 dBm | 7 dBW |
| 40 dBm | 10 dBW |
| 50 dBm | 20 dBW |
| 60 dBm | 30 dBW |
About the units
Decibel-milliwatt (dBm)
Power level relative to 1 mW: 0 dBm = 1 mW, 30 dBm = 1 W, −30 dBm = 1 µW. It is a logarithmic level: 0 dBm corresponds to 0.001 W.
Decibel-watt (dBW)
Power level relative to 1 W: dBW = dBm − 30. It is a logarithmic level: 0 dBW corresponds to 1 W.
Frequently asked questions
What is the formula to convert dBm to dBW?
dBW = dBm − 30. Both are decibel scales with different reference levels, so they differ by a constant.
What is −3 dBm in dBW?
−3 dBm = −33 dBW.
Is this dBm to dBW converter accurate?
Yes. Both units are defined exactly in terms of SI units, so the conversion factor is exact; results are shown to 12 significant figures by default and you can change precision in the converter. Calculations run in your browser using the same tested engine that generated this page.