The Circle of Fifths, Explained by Playing
The circle of fifths is a map of all 12 keys laid out so that every step clockwise rises a perfect fifth and adds a sharp, and every step the other way adds a flat. It is the single most useful diagram in music theory: once it clicks, key signatures, related keys and chord progressions all fall into place, because most of harmony is simply movement around this circle.
Understand the circle by playing it
The game's stages walk around the circle of fifths as you improve. See a chord, play it, know instantly if you nailed it. No download, no signup. MIDI or microphone.
▶ Try ChordRunner Free Free in the browser - practise keys in circle-of-fifths order.What the circle shows
Start at the top with C major, no sharps and no flats. Move one step clockwise and you land on G, which has one sharp. Another step gives D with two sharps, and so on: each clockwise move up a fifth adds exactly one sharp. Go anticlockwise from C instead and you pick up flats one at a time, F, Bb, Eb. The circle turns the abstract idea of key signatures into a simple count of steps.
Explore the circle
Click any key to see its sharps or flats and its relative minor.
C major
no sharps or flats
Relative minor: A minor
Keys, sharps and flats
The circle is the fastest way to recall any key signature. C is empty; each clockwise step adds a sharp in a fixed order (F, C, G, D, A, E), and each anticlockwise step adds a flat in the reverse order (B, E, A, D, G). At the bottom the sharp and flat sides meet at Gb, which is the same set of pitches as F#. Learn the circle and you never have to memorise twelve separate key signatures again, you just count steps from C.
The game progression that walks the circle
The circle is not just theory to memorise; it is a practice order. In ChordRunner, the stage progression moves around the circle of fifths as you improve, so the keys you drill shift by fifths into closely related territory rather than jumping randomly. That means each new key shares most of its notes with the last, so it builds on what you just learned. It pairs naturally with diatonic chords and chord progressions, which both live on the circle.
Practise the circle in the game
Open the game and play through the stages: as you progress, watch the keys move by fifths around the circle, C to G to D and on, each one a small step from the last. Play the chords on your MIDI keyboard or into your microphone and get told instantly whether you were right. Hearing related keys back to back is what finally makes the circle click. Free in the browser, nothing to install.
Common questions
What is the circle of fifths?
The circle of fifths is a diagram of the 12 keys arranged so each step clockwise moves up a perfect fifth and adds one sharp, while each step anticlockwise moves down a fifth and adds one flat. It shows at a glance how keys relate, how many sharps or flats each has, and which chords sit close together.
How do I use the circle of fifths?
Use it to find key signatures (count the steps from C), to find closely related keys (neighbours on the circle share almost all their notes), and to build progressions, since most chord movement in music is a step around the circle, like the V to I of a cadence.
Why do chords a fifth apart sound good together?
Because they share the most notes. A perfect fifth is the most consonant interval after the octave, and neighbouring keys on the circle overlap by all but one note, so moving between them feels smooth. The strongest resolution in music, V to I, is exactly one step around the circle.
How does ChordRunner use the circle of fifths?
The game's stage progression walks around the circle of fifths: as you improve, the keys you practise move by fifths rather than jumping randomly, so you learn related keys in a musical order. You play the chords on a MIDI keyboard or through your microphone with instant feedback.