How chords are built from a scale

A chord is three or more notes played together.

On a guitar that usually means a shape you copied from a diagram. This page is about where those shapes come from: every chord starts as a few notes picked out of a scale, and once you can see how they’re picked, you can build any chord yourself instead of memorising it.

Major and minor

The C major scale, twice over. The numerals are the same in every major key; only the letters change.

C major scale

ICmajor

major

iiDmminor

minor

iiiEmminor

minor

IVFmajor

major

VGmajor

major

viAmminor

minor

vii°Bdimdiminished

diminished

The move never changes, so why do some rows come out major and some minor? Because the scale’s steps aren’t even. Count the frets between the notes you picked.

C to E is four frets, E to G is three. Four then three makes a major chord. D to F is three, F to A is four. Three then four makes a minor chord. Same two gaps, opposite order.

Two other combinations exist. Three and three makes a diminished chord: B, D, F, the only one in a major key. Four and four makes an augmented chord, which never comes out of a major scale at all; you’ll only meet it built from harmonic or melodic minor.

That’s why every major key has the same pattern of chords: I, IV and V major; ii, iii and vi minor; vii diminished. Nobody chose it. It falls out of where the scale’s one-fret steps happen to be.

The four triads

Put a major chord and a minor chord side by side and the outside is identical. Four plus three and three plus four both add up to seven frets, so the root and the fifth sit in the same place. That’s the frame of the chord. Only the middle note moves, by one fret.

The other two break the frame. A diminished chord is a minor chord with its fifth pulled a fret lower. An augmented chord is a major chord with its fifth pushed a fret higher. That’s why both sound unsettled: the frame that holds major and minor steady is gone.

Cmthird −1

third −1

Cdimthird −1, fifth −1

third −1, fifth −1

Caugfifth +1

fifth +1

E and Em

A guitar shape rarely keeps the notes in stacked order. It doubles some and shuffles others to fit the hand, but it never adds a note that isn’t in the stack.

3 → ♭3

Barre chords

An open chord uses the nut, the strip at the end of the neck, as part of the shape: every open string is held down by it. A barre chord replaces the nut with your first finger. Lay it flat across the strings, make the open shape with your other fingers one fret higher, and you’ve moved the whole chord up the neck.

Nothing inside the shape changes. The distances between its notes stay the same, so the type of chord stays the same. Only the root moves, and the chord’s name moves with it.

FE shape, 1st fretthe nut is the barre

Shape

E shapeA shape

Chord

MajorMinor

Fret

Turn your phone for the horizontal view.

Every barre position

Barre	E shape	A shape
1st fret	F	B♭
2nd fret	F♯	B
3rd fret	G	C
4th fret	A♭	D♭
5th fret	A	D
6th fret	B♭	E♭
7th fret	B	E
8th fret	C	F
9th fret	D♭	F♯
10th fret	D	G
11th fret	E♭	A♭
12th fret	E	A

Take the E shape and barre it at the 1st fret: F. At the 3rd fret: G. At the 5th: A. The chord is always named after the note under your first finger on the low E string, because that’s where the shape keeps its root.

The A shape works the same way, with its root on the A string. Barre it at the 3rd fret and it’s C; at the 5th, D.

Minor works exactly as it did in open position. The Em and Am shapes move the same way and take their names the same way. Two shapes, each with a major and a minor version, give you every major and minor chord there is.

Finding the root

All of this depends on knowing the notes on the two lowest strings, which is less work than it sounds. Natural notes sit two frets apart, except E to F and B to C, which sit side by side. Learn where the natural notes fall on the low E and A strings, and the sharps and flats are simply the frets in between.

Two positions

Every note appears on both low strings, so every chord has two barre positions. C is the A shape at the 3rd fret or the E shape at the 8th. They even start from the same bass note: the A string’s 3rd fret and the low E string’s 8th fret are the same C. What differs is how the notes spread out above it. Most players choose whichever position is closer to where their hand already is.

The C chord in two different positions

Sevenths and ninths

The skip-one move doesn’t have to stop at three notes. The numbers in chord names, 7, 9, 11, 13, simply count how far up the stack you went. A 9 is the 2 an octave higher, an 11 is the 4, a 13 is the 6.

From C

Cmaj7

Cmaj9

B: 11 frets → maj7

From G

F: 10 frets → 7

C major’s seventh chordsCmaj7Dm7Em7Fmaj7G7Am7Bm7♭5

Start with the C chord, stacked from the bottom: C, E, G, each a third above the last. The bracket on the left names the chord.

Skip again and you add a fourth: the seventh. From C in C major: C, E, G, then B. That’s Cmaj7. The shaded row says how far up the seventh is, and which kind it makes.

Skip again and you reach D: Cmaj9. Keep going and you run out of notes: C, E, G, B, D, F, A. That’s every note of the scale, stacked in thirds. The dashed blocks are past the octave.

Build the same stack from G and something changes: G, B, D, then F. Not F♯: C major has F, so the scale hands G an F. That’s a different seventh, ten frets above the root instead of eleven, and it makes G7, not Gmaj7.

Under the stacks, the seventh chord on each note of C major, in order from C.

So the scale chooses the seventh. Stack from each note of C major and the sevenths come out in a fixed pattern: maj7 on C and F, m7 on D, E and A, a plain 7 on G, and m7♭5 on B. Every major key repeats it.

C7 vs Cmaj7

C7 isn’t on that list. It needs B♭, and C major doesn’t have one. C7 is what you get by stacking from C inside F major, where C is the fifth note and B♭ belongs to the key: the same job G7 does in C. That’s also where its pull comes from.

The tritone

So from a plain C chord, the next note you add decides the family. B makes Cmaj7, B♭ makes C7, and from either one, a D on top gives Cmaj9 or C9.

CC E G
- +B (7th)
  Cmaj7C E G B
  - +D (9th)
    Cmaj9C E G B D
- +B♭ (♭7th)
  C7C E G B♭from F major
  - +D (9th)
    C9C E G B♭ D
- +A (6th)
  C6C E G A
- +D (9th)
  Cadd9C E G Dno seventh

Chord symbols

Chord names only write down what changed. A plain C means root, major third and perfect fifth, and everything else is measured from there.

The one that catches everyone: a 7 on its own means the lower seventh, B♭ over C. The higher one has to be asked for by name: maj7. And a 9 on its own brings that lower seventh with it. To add the 9 without any seventh, the name has to say add9.

Symbol	Means	Example
(nothing)	root, 3, 5	C = C E G
m	third a fret lower	Cm = C E♭ G
7	adds ♭7 (10 frets up)	C7 = C E G B♭
maj7	adds 7 (11 frets up)	Cmaj7 = C E G B
m7	minor + ♭7	Cm7 = C E♭ G B♭
9	adds 9 and ♭7	C9 = C E G B♭ D
maj9	adds 9 and 7	Cmaj9 = C E G B D
add9	adds 9, no seventh	Cadd9 = C E G D
6	adds 6	C6 = C E G A

Leaving notes out

Cmaj9 has five notes, and something has to go. It’s almost always the fifth: it adds the least, because major and minor chords share it. The usual shape, × 3 2 4 3 ×, plays C, E, B and D. No G, and nobody misses it. Even open C7 leaves the G out.

The open C shape shows the rest of this section in your hand. Lift the finger on the B string, and its C drops to the open B: Cmaj7. Put a finger on the G string’s 3rd fret instead and you’ve added B♭: C7.

Cmaj7

lift one finger: R → 7

add B♭ · no G

Cmaj9

no G

Sus and power chords

Some chords leave the third out on purpose. Without it, a chord is neither major nor minor, and it sounds that way: open, unfinished, waiting.

A sus chord swaps the third for a neighbour. “Sus” is short for suspended: the third is held off, and the ear expects it back.

A power chord is root and fifth, often with the root doubled on top, written C5. With no third to clash, it fits over major and minor alike. Under heavy distortion, where a third turns muddy, it’s often the only chord that sounds clean.

Cfor reference

for reference

Csus22 in place of 3

2 in place of 3

Csus44 in place of 3

4 in place of 3

C5root and fifth only

root and fifth only

D, Dsus4, Dsus2

Open D shows both sus chords with one finger. D is × × 0 2 3 2, with F♯ on the high E string. Move that finger up a fret to G: Dsus4. Lift it off to the open E: Dsus2.

D, Dsus4, back to D is one of the most common moves in acoustic guitar music. Now you know what it is: the third, held off and let back.

Dsus4

F♯ → G

Dsus2

F♯ → open E

root, fifth, root

Slash chords

A chord’s lowest note doesn’t have to be its root. C with E at the bottom is still C, with the same three notes, but it sits differently: lighter, less planted. Charts write it with a slash, C/E. The letter before the slash is the chord; the letter after it is the bass note.

On a guitar this happens all the time without anyone noticing. Strum all six strings of the open C shape and the open low E becomes the lowest note: that’s C/E. Fret G on the low E string’s 3rd fret instead and it’s C/G.

lowest note: C · root

C/E

lowest note: E · third

C/G

lowest note: G · fifth

Moving the bass

Most slash chords exist for one reason: to make the bass move by step instead of jumping. G, D/F♯, Em: the chords are G, D and Em, but the bass walks G, F♯, E, one note at a time down the scale. Without the slash, the bass would leap up to D and back down again.

bass: G · fret 3

D/F♯

bass: F♯ · fret 2

bass: E · open

It’s the same idea as the smooth voices on the intervals page, applied to the lowest note.

Three voices

Try it

Pick any scale page and build its chords yourself with the skip-one move before you look at its chord table. Then check.

Where nextWhat each interval does The tritone