The fretboard below show the notes for a Viola when "Standard Tuning" is used. The strings are tuned to the following notes:
C3G3D4A4
For other alternatives see the available tunings for Viola
The tuner is fully chromatic but if you need a reference of a specific tuning when tuning by ear or if you want to tune any other instrument follow the steps in how to setup the guitar tuner for other instruments