Decibel-watt to Decibel-milliwatt Converter
0 dBW is 30 dBm. Convert decibel-watts (dBW) to decibel-milliwatts (dBm) below: type a value and the result updates as you type.
dBW to dBm calculator
Result
Decibel-watt to Decibel-milliwatt conversion
1 dBW = 31 dBmone decibel-watt in decibel-milliwatts
1 dBm = -29 dBWone decibel-milliwatt in decibel-watts
Decibel-watt (dBW): Power level relative to one watt: 10 times the base-10 logarithm of the power in watts. 0 dBW is 1 W.
Decibel-milliwatt (dBm): Power level relative to one milliwatt: 10 times the base-10 logarithm of the power in milliwatts. 0 dBm is 1 mW and 30 dBm is 1 W.
Source:IEC 60027-3:2002, Logarithmic and related quantities, and their units
How to convert decibel-watts to decibel-milliwatts
To convert decibel-watts to decibel-milliwatts, add 30 decibels.
Formula
dBm = dBW + 30
Examples
- 0 dBW = 0 + 30 = 30 dBm
- 10 dBW = 10 + 30 = 40 dBm
- 30 dBW = 30 + 30 = 60 dBm
Decibel-watt to Decibel-milliwatt conversion table
| Decibel-watt (dBW) | Decibel-milliwatt (dBm) |
|---|---|
| -30 dBW | 0 dBm |
| -20 dBW | 10 dBm |
| -10 dBW | 20 dBm |
| 0 dBW | 30 dBm |
| 3 dBW | 33 dBm |
| 10 dBW | 40 dBm |
| 13 dBW | 43 dBm |
| 20 dBW | 50 dBm |
| 30 dBW | 60 dBm |
| 40 dBW | 70 dBm |
| 50 dBW | 80 dBm |
Values rounded to 10 significant digits where needed.
Frequently asked questions
- What is 0 dBW in dBm?
- 0 dBW is 30 dBm. To convert decibel-watts to decibel-milliwatts, add 30 decibels.
- How do I convert decibel-milliwatts to decibel-watts?
- To convert decibel-milliwatts to decibel-watts, subtract 30 decibels. The formula is dBW = dBm − 30.
- Is this conversion exact?
- Yes. Both units have exact definitions and the factor 30 is exact. Displayed results are only rounded when they have many decimal places.