Number System Trainer

Learn

Start here — learn the numbers with a song you know

Read Charts

4 levels — basic triads up to slash chords

Transpose

Move a full progression to any key

Ear Training

4 levels — can you name the chord just by listening?

Play Along

Piano & guitar shapes in every key — capo tips too

Circle of 5ths

Tap any key to see all 7 chords