Circle of Fifths.

How to use it

Reading the ring

The outer ring is the twelve major keys. The inner ring is their relative minors, the minor key that shares the exact same notes and key signature as the major just outside it. C major and A minor use only the white keys; they sit together at the top.

Key signatures at a glance

Start at C at the top, which has no sharps or flats. Every step clockwise adds one sharp: G has one, D has two, A has three, and so on. Every step counterclockwise from C adds one flat: F has one, B flat has two, E flat has three. The position on the circle is the number of sharps or flats, which is why you never have to memorise them all.

Finding chords that belong together

Here is the part guitar players actually use. For any key, its three primary chords, the I, IV and V, are the key itself and its two immediate neighbours on the circle. In G, that is G, C and D. A huge share of songs never leave those three chords, and the reason they sound "right" together is that they sit side by side here. Click a key and the tool marks its IV and V for you.

Relative minors and sad-happy swaps

Because a major and its relative minor share every note, you can slide between them for free. A song in C that wants a darker moment can lean on A minor without changing key. The inner ring shows you which minor pairs with which major instantly.

Smooth key changes

Moving to a neighbouring key changes only one note in the signature, so it feels smooth. Jumping across the circle changes many notes at once and feels dramatic. That is why so many key changes step just one place clockwise, the classic final-chorus lift.

Put it to work with the chord library for the shapes and the fretboard explorer to see the key laid out on the neck.