Choose a major key. Its neighbors mark IV and V; the inner ring gives relative minors. At paired positions, choose either spelling.
An outline marks each neighbor; a filled button marks your key. Signature counts sit between the rings. Paired names share piano keys in equal temperament.
C major · no sharps or flats
IV: F major · V: G major · Relative minor: A minor
Tap a chord to hear its notes. At the ends of the sharp and flat spellings, IV or V may appear on the circle under an enharmonic name.
| Major key | Key signature, in order | Relative minor | I ii iii IV V vi vii° |
|---|---|---|---|
| C major | No sharps or flats | A minor |
|
| G major | 1 sharp: F♯ | E minor |
|
| D major | 2 sharps: F♯ C♯ | B minor |
|
| A major | 3 sharps: F♯ C♯ G♯ | F♯ minor |
|
| E major | 4 sharps: F♯ C♯ G♯ D♯ | C♯ minor |
|
| B major | 5 sharps: F♯ C♯ G♯ D♯ A♯ | G♯ minor |
|
| C♭ major | 7 flats: B♭ E♭ A♭ D♭ G♭ C♭ F♭ | A♭ minor |
|
| F♯ major | 6 sharps: F♯ C♯ G♯ D♯ A♯ E♯ | D♯ minor |
|
| G♭ major | 6 flats: B♭ E♭ A♭ D♭ G♭ C♭ | E♭ minor |
|
| C♯ major | 7 sharps: F♯ C♯ G♯ D♯ A♯ E♯ B♯ | A♯ minor |
|
| D♭ major | 5 flats: B♭ E♭ A♭ D♭ G♭ | B♭ minor |
|
| A♭ major | 4 flats: B♭ E♭ A♭ D♭ | F minor |
|
| E♭ major | 3 flats: B♭ E♭ A♭ | C minor |
|
| B♭ major | 2 flats: B♭ E♭ | G minor |
|
| F major | 1 flat: B♭ | D minor |
|
Reading the circle
Start at C, which has no signature accidentals. Moving clockwise takes you up a perfect fifth: C to G, G to D. Each step adds a sharp through C♯ major. Counterclockwise, C to F to B♭ adds flats, continuing through C♭ major. The three paired positions keep both conventional spellings visible.
Sharps enter the signature in this order: F, C, G, D, A, E, B. Flats reverse that order: B, E, A, D, G, C, F. The table spells every accidental, including E♯ in F♯ major and F♭ in C♭ major. A signature applies to those note letters in every octave unless the score changes them with accidentals.
The inner ring names each major key's relative minor, which shares its signature. D major and B minor both have F♯ and C♯. Sharing a signature does not make their tonal centers the same.
Finding chords in a key
Build a triad on each scale note by taking alternate notes from that scale. In F major, the second degree gives G–B♭–D: G minor. The seventh gives E–G–B♭: E diminished.
Uppercase Roman numerals mark major triads; lowercase marks minor triads. The small circle on vii° means diminished. These seven chords use only notes from the major scale. Songs can also use chords from outside that set.
Progressions and transposing
I–V–vi–IV in C is C–G–Am–F. Choose D and the same degrees become D–A–Bm–G. To transpose, keep each chord's degree and quality while changing the key. A melody must move by the same interval as the chords.
A ii–V–I in C uses Dm–G–C. In jazz, those chords often include sevenths: Dm7–G7–Cmaj7. The circle's chord buttons play triads; the piano chord chart includes seventh chords. Guitar players can find playable shapes in the guitar chart.
For work on hearing these relationships, see music theory and ear training lessons at B# Music in Charlottesville.
Questions
Is the circle of fourths different from the circle of fifths?
It is the same arrangement read in the opposite direction. C up to F spans a perfect fourth; F up to C spans a perfect fifth. Both routes visit all twelve pitch classes.
How do I find a song's key?
Listen for the note or chord that feels like home, then check the melody and harmony against it. A key signature narrows the possibilities, but it does not by itself distinguish a major key from its relative minor. The final chord is a clue, not a guarantee.
Why does a minor key sometimes use extra sharps?
Minor-key music often raises scale degree seven to lead into the tonic. A minor has no signature sharps, yet an E major chord uses G♯. That raised note is written as an accidental; it does not change the signature to A major.
Are F sharp and G flat the same note?
On an equal-tempered piano they sound at the same pitch. Their written names describe different positions in a scale: F♯ major needs E♯, while G♭ major needs C♭. Keeping those letters correct makes intervals and chord structure easier to read.
