Milliwatt to Decibel-milliwatt Converter
1 mW is 0 dBm. Convert milliwatts (mW) to decibel-milliwatts (dBm) below: type a value and the result updates as you type.
mW to dBm calculator
Result
Milliwatt to Decibel-milliwatt conversion
1 mW = 0 dBmone milliwatt in decibel-milliwatts
1 dBm ≈ 1.258925412 mWone decibel-milliwatt in milliwatts
Milliwatt (mW): One thousandth of a watt.
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:Milliwatt: SI Brochure, 9th edition (BIPM, 2019); Decibel-milliwatt: IEC 60027-3:2002, Logarithmic and related quantities, and their units
How to convert milliwatts to decibel-milliwatts
To convert milliwatts to decibel-milliwatts, take the base-10 logarithm of the amount, then multiply by 10.
Formula
dBm = 10 × log₁₀(mW)
Examples
- 1 mW = 10 × log₁₀(1) = 0 dBm
- 10 mW = 10 × log₁₀(10) = 10 dBm
- 100 mW = 10 × log₁₀(100) = 20 dBm
Milliwatt to Decibel-milliwatt conversion table
| Milliwatt (mW) | Decibel-milliwatt (dBm) |
|---|---|
| 0.001 mW | -30 dBm |
| 0.01 mW | -20 dBm |
| 0.1 mW | -10 dBm |
| 1 mW | 0 dBm |
| 2 mW | 3.010299957 dBm |
| 5 mW | 6.989700043 dBm |
| 10 mW | 10 dBm |
| 20 mW | 13.01029996 dBm |
| 50 mW | 16.98970004 dBm |
| 100 mW | 20 dBm |
| 500 mW | 26.98970004 dBm |
| 1000 mW | 30 dBm |
Values rounded to 10 significant digits where needed.
Frequently asked questions
- What is 1 mW in dBm?
- 1 mW is 0 dBm. To convert milliwatts to decibel-milliwatts, take the base-10 logarithm of the amount, then multiply by 10.
- How do I convert decibel-milliwatts to milliwatts?
- To convert decibel-milliwatts to milliwatts, divide the level by 10, raise 10 to that power. The formula is mW = 10^(dBm ÷ 10).
- Is this conversion exact?
- Yes. Both units have exact definitions and the factor 1 is exact. Displayed results are only rounded when they have many decimal places.