The circle of fifths is a diagram that lays the twelve musical keys out in a ring, each one a perfect fifth from its neighbours. It is really a map. It shows at a glance how many sharps or flats a key carries, which keys are close relatives that share most of their notes, and why chords tend to pull the way they do. Learn to read it and a good deal of harmony stops being something to memorise.
Plain theory, no instrument required. It reads the same whether you play piano, guitar, or write in a piano roll, in any key and any style.
The circle of fifths is a diagram that arranges the twelve keys of Western music in a circle, with each key a perfect fifth apart from the ones beside it. C sits at the top, and moving one step clockwise takes you up a perfect fifth to the next key, on and on until, after twelve steps, you arrive back at C.
A perfect fifth is the gap of seven semitones between a note and the fifth note of its major scale, one of the most consonant distances in music. From C that fifth lands on G, from G it lands on D, and so on. Because stacking twelve of these fifths happens to close neatly back onto your starting note, the whole set of keys forms a loop rather than a line, which is why it is drawn as a circle.
Nothing about it is a piece you play. It is a reference map you read, and almost everything it tells you falls out of that one idea of stepping round by fifths. The rest of this guide walks the circle in both directions and shows what each part of the map is for.
Going clockwise, every step moves up a perfect fifth and adds one sharp to the key signature. Going counterclockwise, every step moves down a perfect fifth and adds one flat. C sits at the top with no sharps or flats at all, and the two directions fan out from there.
Start at C and step clockwise. Each move up a fifth adds one sharp, so the keys read C, G, D, A, E and B. Carry on and you reach F sharp, six sharps in, usually written F# or, spelled the other way, Gb. From that point at the bottom the names are easier to read as flats, and the count of flats falls back toward none: Db, Ab, Eb, Bb, F, and home to C. Go the other way instead, counterclockwise from C, and each step moves down a fifth, which is the same as up a fourth, and adds one flat, so the flat side reads C, F, Bb, Eb, Ab, Db.
| Clockwise from C | Major key | Sharps or flats | Relative minor |
|---|---|---|---|
| Top | C | none | A minor |
| 1 | G | 1 sharp | E minor |
| 2 | D | 2 sharps | B minor |
| 3 | A | 3 sharps | F# minor |
| 4 | E | 4 sharps | C# minor |
| 5 | B | 5 sharps | G# minor |
| 6 | F# / Gb | 6 sharps / 6 flats | D# / Eb minor |
| 7 | Db | 5 flats | Bb minor |
| 8 | Ab | 4 flats | F minor |
| 9 | Eb | 3 flats | C minor |
| 10 | Bb | 2 flats | G minor |
| 11 | F | 1 flat | D minor |
The bottom of the circle is where the two spellings meet. F sharp and G flat name the same six pitches written two different ways, so you will see the position labelled either way depending on which is tidier to read. That overlap is normal, and it is why the sharp side and the flat side join up instead of running off the edge.
The circle does two jobs at once. It counts the sharps or flats in every key, and it places related keys side by side. A key's position tells you its signature, and its neighbours are the keys that sound closest to it.
The count is just the position. Because each clockwise step from C adds exactly one sharp and each counterclockwise step adds exactly one flat, how far a key sits from the top is how many accidentals it carries. One step clockwise is one sharp, three steps is three sharps, and the same the other way for flats. You can read a key signature straight off the diagram without working it out note by note.
Two keys next to each other on the circle differ by a single note in their scales, so they share six of their seven notes. C major and G major are one step apart, and the only note that separates them is F against F sharp. That heavy overlap is what makes neighbouring keys sound closely related, and it is why a move to a neighbour is the smoothest kind of key change.
Alongside the majors sits a second ring. Every major key has a relative minor, a minor key that uses the exact same notes and so carries the same key signature, drawn on an inner circle at the same position. The relative minor starts a minor third below the major, which is the same as starting on the sixth note of the major scale, so C major pairs with A minor, G major with E minor, and so on round the ring. Reaching for a minor colour without leaving your set of notes is often just a matter of treating the inner ring as home instead of the outer one.
In practice the circle is a shortcut for three everyday jobs: finding a key's chords and signature, changing key smoothly, and seeing why chords pull the way they do. The pulling is the part it explains best, because the strongest motion in this kind of harmony is motion by a fifth, which is exactly what the circle is built from.
The clearest case is the pull home. The dominant chord, V, is built on the note a fifth above the home note, which puts it one step clockwise from home on the circle. Moving from V back to I, one step counterclockwise, tends to give the strongest sense of arrival in this kind of harmony, and it is the pull that closes a great many pieces. In C major that is the move from G back to C.
The ii V I progression is the same pull stretched over three chords, and on the circle its roots are simply three neighbours in a row. In C major that is D minor, then G, then C, whose roots D, G and C sit side by side as you travel counterclockwise toward home. Because each root drops a fifth to the next, the progression tends to feel like it is steadily homing in, which is part of why it turns up everywhere from jazz to pop.
The circle also shows you where the smooth exits are when you want to change key. Step to either neighbour and you land in a key that shares all but one note with the one you left, so the change can slip by almost unnoticed. Leap to the far side of the circle instead and the same kind of move tends to sound sudden and dramatic, because the two keys have far fewer notes in common. Writers lean on both, depending on whether they want the join to disappear or to land.
All of this assumes you are comfortable with what a key is in the first place. If that idea is shaky, our guide to scales and keys lays the groundwork the circle sits on. And once you are using the circle to choose chords, our guide to writing a chord progression takes those chords and puts them in an order that moves.
We built ARGISH to make this part audible. It is a self-playing chord synth: set a key and it builds chords and whole progressions that stay in that key, so you can hear how the pull of a fifth leans toward home, and how two neighbouring keys share almost all their notes, without placing a single note yourself or reading the diagram at all. It is a fast way to turn the map above into something you can actually hear.
It runs free in your browser to try, and installs as AU, VST3, AAX or a standalone app when you want it inside your own sessions.
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