Circle of fifths

Twelve keys on one wheel. Turn it to find the key of a song, name its chords by number, move the song to the singer's key, and write your own. Nine short lessons, each with one thing to try.

Mode

Note names

Sevenths

C majorNo sharps or flats. Relative minor A minor.

Lesson 1 of 9

Read the wheel

Start at the top. C. One step clockwise is G, a fifth above C. Another step is D, a fifth above G. Keep going and after twelve steps you are home again. Go the other way and you fall by fifths: F, then B flat, then E flat.

Three rings sit on that circle. The inner ring holds the major chords. The middle ring holds the minor chords. The outer ring holds the diminished chords.

The window with the bold edge is a key. It frames seven chords: three majors, three minors, one diminished. Those seven are the family of the key. Every song that stays in one key is built from them. The small box that says KEY points at the home chord, the one the song rests on. The pointer under it reaches into the center and shows how many sharps or flats the key carries.

Turn the window one step and only one chord in each ring changes. Two keys that sit side by side share most of their family. That is why songs slip so easily between neighbors.

Turn the wheel to G. Which diminished chord sits in the window?

Workbench

The lessons use these tools in a fixed order. Here they are free. Type a song's chords, find its key, read its numerals, move it, and check the scale and the spelling of every chord.

Find the key and move the song

Chords, in order, separated by spaces

Write sharps as # and flats as b. Dm, Gm7, Cmaj7, A7, F#m7b5, Bdim and Asus4 are all understood. A slash bass note is ignored: the bass changes how a chord is voiced, not which chord it is.

Emiii

DII

Keys that hold these chords

The song begins on Em, the iii of C major. Songs usually begin on their I or their vi. Em is the vi of G major, that is, the home of E minor. Try that key too, if its chords fit.

Move it to

The scale

The seven notes of C major in order from the home note. No sharps or flats.

The chords, spelled

Every chord in the key is built from every other note of its scale. Click a chord on the wheel or in this table.

Chord	Numeral	Notes	Seventh
C	I	C E G	Cmaj7: C E G B
Dm	ii	D F A	Dm7: D F A C
Em	iii	E G B	Em7: E G B D
F	IV	F A C	Fmaj7: F A C E
G	V	G B D	G7: G B D F
Am	vi	A C E	Am7: A C E G
B°	vii°	B D F	Bm7♭5: B D F A

Key signature

C major: no sharps or flats. Its relative minor, A minor, shares it.

Chord formulas

Type	Formula	From C	Written
major	1 3 5	C E G	C
minor	1 ♭3 5	C E♭ G	Cm
diminished	1 ♭3 ♭5	C E♭ G♭	C°
major seventh	1 3 5 7	C E G B	Cmaj7
dominant seventh	1 3 5 ♭7	C E G B♭	C7
minor seventh	1 ♭3 5 ♭7	C E♭ G B♭	Cm7
minor seven flat five	1 ♭3 ♭5 ♭7	C E♭ G♭ B♭	Cm7♭5

The circle of fifths is older than any book about it. The wheel, the lessons and the examples on this page are MeloFolio's own, and every chord name and numeral is computed from the circle, not typed in.

How to read it