dBm stands for decibels (dB) relative to one milliwatt. It is an absolute unit of power.

This tool adds any number of dBm power values to compute the total power.

Simply enter the powers in dBm with each number separated by a Comma.

**Explanation** of how to add dBm

Note that since dBm is a logarithmic value, dBm values cannot be added directly.

Instead we have to:

- Convert dBm to Watt
- Add Watt values
- Convert the result in Watt back to dBm

**Example calculation**

The sum of power levels 30 dBm and 3 dBm is **30.01 dBm** (not 33 dBm).

The sum of three powers 40 dBm, 30 dBm and 10 dBm is **40.42 dBm**