Red–green covers deuteranopia and protanopia, blue–yellow covers tritanopia, and high contrast drops colour altogether. Every dot is labelled and roots are filled, so the board never relies on colour alone.
Fret number, 1 to 24. Leave it empty for no capo. Notes behind the capo are hidden, since you can’t play them.
Tap any note on a fretboard to hear it.
By ear, or by microphone.
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Listening is off
Damp the other strings as you tune: two strings ringing at a similar volume can only be told apart by which one you meant. The microphone is used solely in your browser to work out the pitch — nothing is recorded or sent anywhere.