RSSI to dBm Calculator

This tool calculates the dBm (deciBel relative to 1 milliwatt) value from the RSSI (Received Signal Strength Indicator)


  • Enter the value for RSSI
  • Optional: Modify the minimum and maximum values for RSSI and dBm

The tool will calculate the equivalent value in dBm

Example Calculation

Under the following conditions:


An RSSI value of 127 is equivalent to -60 dBm

RSSI vs dBm

RSSI (Received Signal Strength Indicator) and dBm (decibels relative to a milliwatt) are both metrics used to measure the signal strength of a wireless connection, but they differ in their scale and the way they are used.


  • RSSI is a comparative measure of the received signal strength in a wireless environment, typically measured in arbitrary units from 0 (min) to 255 (max). The closer the RSSI value is to 255, the stronger the signal.
  • The value of RSSI indicates the actual power level being received after all possible environmental losses and antenna gains have been factored in.
  • RSSI values are not standardized across vendors; therefore, the interpretation of what constitutes a “good” or “bad” RSSI value can vary between wireless devices and vendors. (In the case of Ring devices for example, RSSI values are equivalent to dBm). However there are general rules of thumb in terms of range where the signal will be good.
  • Because of its relative nature, RSSI is often used for simple signal strength indications such as displaying signal bars on a smartphone.


  • dBm, on the other hand, is an absolute measure of signal strength in milliwatts, expressed in logarithmic scale. It is defined as the power ratio in decibels (dB) of the measured power referenced to one milliwatt (mW).
  • dBm provides a more precise and consistent measure of signal strength. For Wi-Fi signals, values are typically in the range of -30 dBm (very strong signal) to -100 dBm (very weak signal).
  • Since dBm is a standardized unit of measure, it offers a consistent reference for measuring and comparing signal strength across different devices and technologies.
  • dBm is widely used in technical and engineering settings to accurately assess signal strength and quality.

While RSSI provides a more generalized and device-specific indication of signal strength, dBm offers a precise, absolute measurement that can be consistently applied across different contexts.

Wikipedia References