What chords are in each key — all twelve, on one page

A key has seven chords in it. Not "mostly seven", not "seven and some others you might get away with" — seven, always, in every key, in the same order and the same pattern of major and minor. Learn the pattern once and you have learned all twelve keys.

This is the sheet I write out for students, and it is the single most useful piece of paper in the room. Songwriters use it to find the chord they can hear but cannot name. Guitarists use it to work out what key a song is in. Everyone eventually uses it to stop guessing.

How to read it

The Roman numerals across the top number the chords of the key. Capitals are major chords, small letters are minor ones, and the pattern never changes:

I · ii · iii · IV · V · vi · vii°

So in any key at all: the first chord is major, the second and third are minor, the fourth and fifth are major, the sixth is minor, and the seventh is a diminished chord that we will come back to. Find your key in the left-hand column and read across.

Read the rows downwards and you are walking round the circle of fifths — each key's home chord is a fifth above the one above it, and C♯ at the bottom is A♭ at the top again, spelled differently. F♯ is the same set of sounds as G♭, and C♯ the same as D♭; which spelling you use depends on the music in front of you, not on the guitar.

The seventh chord, and why I cross it out

The chord built on the seventh degree is diminished, and in rock, pop, folk and blues you will almost never play it. It is not that it is forbidden — it does real work in classical music and in jazz — but if you are learning to accompany songs, it will not come up, and worrying about it early costs you attention you need elsewhere. Treat the last column as information rather than homework.

What that leaves you with is six chords per key, and the great majority of songs you know are built from four of those six.

Two chords from outside the key that turn up constantly

Sometimes a song uses a chord that is not in its key at all, and there are two of these that appear so often it is worth knowing them by name rather than being ambushed by them.

The major version of chord ii

Chord ii is minor. Make it major instead and it becomes a signpost pointing at chord V — so it is almost always followed by chord V, or by chord IV on the way there.

In the key of C, chord ii is D minor. Play D major instead:

| C | D | G | C |  or  | C | D | F | C |

That lift you can hear on the D is one note changing — F to F♯ — and that one note is borrowed from outside the key. It is the oldest trick in the book and it still works every time.

Chord IV of chord IV

Take chord IV of your key, then ask what its chord IV would be, and play that. It is usually followed by the real chord IV, and then home to I.

In the key of C, chord IV is F. The chord IV of F is B♭. So:

| B♭ | F | C |

Every listener has heard that ending a thousand times without ever knowing it steps briefly outside the key to get there. It has a name, as it happens — the double plagal cadence — and Ethan Hein has a page of songs to hear it in, starting with the end of "Hey Jude".

Using this to work out what key a song is in

Write down the chords of the song. Find the row in the table above that contains all of them. That is your key — and if one chord will not fit, look at the two borrowed chords above before assuming you have got it wrong.

Then the last check, which the table cannot do for you: play the song and stop. The chord your ear wants to hear next is chord I, and your ear will be right. The table is for confirming what you already half-know, not for replacing the knowing.

Where this goes next

Knowing the chords of a key is one half of it; the other half is knowing which notes to play over them, which is the same information seen from the other end. Those are on the scales and modes page, and the shape most guitar solos actually come from is on the minor pentatonic page.