Milliwatt to dBm Conversion Reference Table
Quick reference chart for converting milliwatts (mW) to decibel-milliwatts (dBm). Use this table for RF engineering, wireless communications, and signal power calculations.
Watt (W), Milliwatt (mW) to dBm Conversion Table
| Power (mW) | Power (dBm) |
|---|---|
| 0.01 mW | -20 dBm |
| 0.1 mW | -10 dBm |
| 1 mW | 0 dBm |
| 2 mW | 3 dBm |
| 3 mW | 4.8 dBm |
| 4 mW | 6 dBm |
| 5 mW | 7 dBm |
| 6 mW | 7.8 dBm |
| 7 mW | 8.5 dBm |
| 8 mW | 9 dBm |
| 9 mW | 9.5 dBm |
| 10 mW | 10 dBm |
| 100 mW | 20 dBm |
| 1,000 mW (1 W) | 30 dBm |
| 10,000 mW (10 W) | 40 dBm |
| 100,000 mW (100 W) | 50 dBm |
| 1,000,000 mW (1 kW) | 60 dBm |
| 10,000,000 mW (10 kW) | 70 dBm |
| 100,000,000 mW (100 kW) | 80 dBm |
| 1,000,000,000 mW (1 MW) | 90 dBm |
| 10,000,000,000 mW (10 GW) | 100 dBm |
mW to dBm Conversion Formula
dBm Definition: dBm is the power ratio in decibels (dB) of the measured power referenced to one milliwatt (mW).
The formula below can be translated as: "the power P(dBm) in dBm is equal to 10 times the base 10 logarithm of the power P(mW) in milliwatts divided by 1 milliwatt":
P(dBm) = 10 · log10(P(mW) / 1mW)
So, for P = 1 mW is equal to 0 dBm
Example:
Convert 100 mW to dBm:
P(dBm) = 10 · log10(100mW / 1mW) = 20 dBm
W to dBW Conversion
The decibel-watt or dBW is the power ratio in decibels (dB) of the measured power referenced to one Watt (W):
P(dBW) = 10 · log10(P(W) / 1W)
Example:
Convert 10 W to dBW:
P(dBW) = 10 · log10(10W / 1W) = 10 dBW
Relationship Between dBm and dBW
Since 1 W = 1000 mW, the relationship is:
- dBW = dBm - 30
- dBm = dBW + 30
Related Power Converters
Use our interactive calculators for precise conversions:
- Watts to dBm Calculator - Convert any watt or milliwatt value to dBm
- dBm to Watts Calculator - Convert dBm values back to watts
Frequently Asked Questions
What is dBm?
dBm (decibel-milliwatt) is a unit of power expressed in decibels referenced to one milliwatt. It's commonly used in RF engineering, telecommunications, and wireless networking to express signal power levels.
Why use dBm instead of mW?
dBm uses a logarithmic scale, making it easier to work with the wide range of power levels encountered in RF systems (from microwatts to megawatts). It also simplifies calculations since gains and losses can be added instead of multiplied.
What is 0 dBm in milliwatts?
0 dBm equals exactly 1 milliwatt (1 mW). This is the reference point for the dBm scale.
How do I convert dBm to dBW?
To convert dBm to dBW, subtract 30: dBW = dBm - 30. For example, 30 dBm = 0 dBW (which equals 1 Watt).