Free tool
Nashville number converter
Turn chords into numbers to see the shape of a song, or numbers into chords for any key. Minor keys count from their relative major, the way church bands read them.
In the key of G
15/76m4
1541
Why numbers
Learn a song once, play it in any key.
A 1, 5, 6m, 4 is the same shape in every key. Once you hear it that way, a key change is just a new starting note. Earshed can show any chart in numbers, and checks the chords you play against them.