All tools
Interactive theory
Circle of Fifths
Click a key to see its relative minor, close modulation choices and diatonic chords.
How the circle of fifths works
The circle arranges keys by perfect fifths, so neighboring keys share most of the same notes. This makes it a fast way to find smooth modulation targets, related minors and chord families that naturally fit together.
Choose sharps or flats depending on how you prefer to write the key. Compatible-keys mode highlights keys with strong note overlap, which is useful for remixing, harmonic mixing and writing bridge sections.
Writing with the circle
Start from the selected major key, borrow color from the parallel minor, or move one step around the circle for a subtle lift. Use the Scale Helper to test note ideas, then generate chord progressions once you have a direction.