Calculate the dB gain or loss between two dBm levels, convert dBm to dBW, dBuW, dBk and watts, and solve for the input or output power level in dBm.
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dBm to dB List Formula
The following formula is used to convert a value in dBm to another dB unit with a different reference power.
Variables:
- dBtarget is the converted value in the selected dB unit
- dBm is the original power level referenced to 1 mW
- offset is the constant adjustment based on the target reference power
Common offsets are -30 for dBW, 0 for dBm, +30 for dBยตW, and -60 for dBk.
In logarithmic form, dBm is defined as the power level relative to 1 mW. When converting to another dB scale, the actual power stays the same and only the numerical value changes because the reference power changes.
What is a dBm to dB List Conversion?
A dBm to dB list conversion changes a power measurement from dBm, which is referenced to 1 milliwatt, into another decibel-based unit such as dBW, dBยตW, or dBk. These units all describe the same power level, but they use different reference powers. Because of that, the conversion is done by adding or subtracting a fixed offset.
For example, 30 dBm equals 0 dBW because dBW is referenced to 1 watt, which is 1000 milliwatts. Likewise, 30 dBm equals 60 dBยตW because dBยตW is referenced to 1 microwatt.
How to Calculate dBm to dB List?
The following steps outline how to convert dBm into another dB unit.
- First, determine the input power level in dBm.
- Next, choose the target dB unit such as dBW, dBm, dBยตW, or dBk.
- Find the correct offset for that unit relative to dBm.
- Calculate the result using dBtarget = dBm + offset.
- After inserting the values and calculating the result, check your answer with the calculator above.
Example Problem:
Convert 30 dBm into dBW, dBยตW, and dBk.
dBW = 30 – 30 = 0 dBW
dBยตW = 30 + 30 = 60 dBยตW
dBk = 30 – 60 = -30 dBk
dBm to dB List Conversion Table
The table below shows how a 30 dBm signal appears in several different dB units.
| Target dB Unit | Reference Power | 30 dBm Expressed in Target Unit |
|---|---|---|
| dBm | 1 mW | 30 dBm |
| dBW | 1 W | 0 dBW |
| dBยตW | 1 ยตW | 60 dBยตW |
| dBk | 1 kW | -30 dBk |
Once you know the reference power used by each dB unit, converting from dBm becomes a simple matter of adding or subtracting the correct constant offset.
