How to convert Wifi signal strength from Quality (percent) to RSSI (dBm)?

Question

How should I convert Wifi signal strength from a Quality in percentage, usually 0% to 100% into an RSSI value, usually a negative dBm number (i.e. -96db)?

Answer 1

Mentioned pseudocode will not work all the ranges, the ranges example (-80dBm to 0, and -40dBm to 100).

Generic simple logic to map any range to 0 to 100. Usage example, for below code ConvertRangeToPercentage(-80,-40,-50)

int ConvertRangeToPercentage (int a_value_map_to_zero, int a_value_map_to_100, int a_value_to_convert)
{

   int percentage = 0;

   if (a_value_map_to_zero < a_value_map_to_100)
   {
      if (a_value_to_convert <= a_value_map_to_zero)
      {
         percentage = 0;
      }
      else if (a_value_to_convert >= a_value_map_to_100)
      {
         percentage = 100;
      }
      else
      {
         percentage = (a_value_to_convert - a_value_map_to_zero) * 100 / (a_value_map_to_100 - a_value_map_to_zero);
      }
   }
   else if (a_value_map_to_zero > a_value_map_to_100)
   {
      if (a_value_to_convert >= a_value_map_to_zero)
      {
         percentage = 0;
      }
      else if (a_value_to_convert <= a_value_map_to_100)
      {
         percentage = 100;
      }
      else
      {
         percentage = (a_value_to_convert - a_value_map_to_zero) * 100 / (a_value_map_to_100 - a_value_map_to_zero);
      }
   }
   else
   {
      percentage = 0;
   }

   return percentage;
}