Reference
The circle of fifths, made interactive: click any key to see its signature, relative minor, and the chords that belong to it — and hear them.
This tool is on the way to the web. Meanwhile, Coco's app already trains the skill it's built around — free to start.
The circle of fifths arranges the twelve keys by their closest harmonic relationships. It's the fastest way to see key signatures, find relative majors and minors, and understand why certain chords and key changes sound natural together.
Use it as a reference while writing, to figure out which chords fit a key, or to plan a key change. Combined with Coco's scale and chord ear training, the circle stops being a diagram to memorize and becomes a map you can actually hear.
FAQ
It maps key relationships — signatures, relative minors, and which chords and modulations sound closely related. It's a core reference for songwriting and theory.
Yes. The interactive version lets you hear each key and chord so the relationships make sense by ear, not just on paper.