Guide · Guitar theory
How chords are built
A chord is three or more notes stacked in 3rds, skipping every other note of the scale. From C, take C, skip D, take E, skip F, take G: C, E and G is C major. Whether each 3rd is major (four The smallest distance in Western music: one fret on the guitar, such as E to F or F to F♯.) or minor (three) decides the chord's quality.
Stacking 3rds
Start on any note, then add the note two letters up, and again: The note a chord is named after and built up from. C is the root of C, Cm and C7., 3rd and 5th make a A three-note chord stacked in 3rds: a root, a 3rd and a 5th. Major, minor, diminished and augmented chords are triads..
Letters do the first part of the work: C, E, G or A, C, E or G, B, D. Every triad spells every other letter. Then the exact distances decide the sound. In C major, C to E is a major 3rd of four The smallest distance in Western music: one fret on the guitar, such as E to F or F to F♯., and E to G a minor 3rd of three; together they span a perfect 5th, C to G, seven half steps.
That outer 5th is the frame of most chords. What sits in the middle, the 3rd, gives the chord its character, which is why guitarists often say the 3rd is the most important note in a chord.
The four triads
Two kinds of 3rd, stacked two ways, give four A three-note chord stacked in 3rds: a root, a 3rd and a 5th. Major, minor, diminished and augmented chords are triads.: major, minor, A chord with a minor 3rd and a flattened 5th, written °. It sounds tense, and is the vii° chord of a major key. and A chord with a major 3rd and a raised 5th, written +. Its notes split the octave into three equal parts..
Major is a major 3rd then a minor 3rd: C, E and G. Minor swaps them, a minor 3rd then a major 3rd: C, E♭ and G is Cm. That one lowered note, E to E♭, is all that separates bright from dark.
Two minor 3rds make a diminished triad, C, E♭ and G♭, written C°: its 5th is a The smallest distance in Western music: one fret on the guitar, such as E to F or F to F♯. short, which makes it tense. Two major 3rds make an augmented triad, C, E and G♯, written C+, with a raised 5th that floats.
In a major key, stacking 3rds on each scale note gives three major chords, three minor chords and one diminished, which is the pattern the chord qualities guide explains.
Adding a 7th
Stack one more 3rd on a A three-note chord stacked in 3rds: a root, a 3rd and a 5th. Major, minor, diminished and augmented chords are triads. and you reach the 7th, which gives five kinds of A triad with one more 3rd on top, the 7th, which makes four notes: G7, Cmaj7 and Am7 are seventh chords. in everyday use.
Open
E shape · fret 3
A shape · fret 10
A major triad with a minor 7th is a A major chord with a minor 7th added, such as G7. It is the V7 of a key and pulls strongly to the I chord.: G7 is G, B, D and F. It is the V7 of C major and pulls hard towards C. With a major 7th instead, Cmaj7 is C, E, G and B, a soft, open sound.
A minor triad with a minor 7th is a minor 7th chord, Am7: A, C, E and G. A A chord with a minor 3rd and a flattened 5th, written °. It sounds tense, and is the vii° chord of a major key. triad with a minor 7th is A diminished triad with a minor 7th added, written m7♭5 or ø7. It is the ii chord of a minor key., Bm7♭5: B, D, F and A, and with a Four notes stacked in minor 3rds, written °7. Every note is the same distance from the next, so the chord pulls hard to the chord a half step above any of its notes. it becomes a diminished 7th chord, B°7.
Every 7th chord on the site has its own page with shapes, for example G7, Cmaj7 and Am7.
Sus, 6th and add9 chords
Change or add one note and a plain chord takes on a new colour without changing its job.
A A chord that replaces its 3rd with a 2nd (sus2) or a 4th (sus4), so it is neither major nor minor and sounds unresolved. replaces the 3rd. Csus4 is C, F and G, with the 4th waiting to fall to the 3rd, and Csus2 is C, D and G. Without a 3rd they are neither major nor minor, which makes them sound open and unresolved.
A 6th chord adds the 6th: C6 is C, E, G and A, sweet and settled. An add9 chord adds the 9th, the 2nd an The distance of twelve half steps, where a note comes round to the same name. Twelve frets up a string is an octave. higher, but keeps the 3rd: Cadd9 is C, E, G and D, still major, just brighter.
On guitar these colours are often one finger away from a chord you know: lift or add a finger on an open D or A chord and you can hear sus2, sus4 and back again.
Chords on the guitar
A guitar chord repeats and reorders these notes across six strings; the name comes from the notes, not their order.
Open C is C, E, G, C and E from the A string up. It doubles the The note a chord is named after and built up from. C is the root of C, Cm and C7. and the 3rd but is still just C, E and G. The lowest note is usually the root; when it is not, the chord is written with a slash, like C/G for C with G in the bass.
Guitarists often leave notes out. The open C7 skips the 5th, and many jazz shapes keep only the root, 3rd and 7th. The 5th adds the least colour, so it is the first note to go.
To work out any chord, find its root, count the 3rd and 5th from it, and listen. The chord chart has every type on all twelve roots, and the glossary explains each term in a line.