What Are 7th Chords?

7th chords chart: the five 7th chord types

Every 7th chord is a triad (root, 3rd, 5th) plus a 7th. Two choices decide the type: is the triad major, minor or diminished, and is the 7th a major 7th (one half step below the octave) or a flat 7th (a whole step below)?

The 𝄫7 (double-flat 7th) in a diminished 7th chord sounds the same as a 6th; it is spelled as a 7th because the chord is built in stacked 3rds.

Hear the difference on A

All six cards below have A as the root. Tap through them in order: the triad changes from major to minor to diminished, and the 7th moves between G♯, G and G♭.

Look at the G string on the first four. In A it plays A (fret 2). In A7 it is open: G, the flat 7th. In Amaj7 it is fret 1: G♯, the major 7th. In Am7 it is open again, and the C on the B string makes it minor. One string carries most of the difference.

Finding the 7th on the neck

Two rules find the 7th from any root:

• Flat 7th: two frets below the root’s octave. A7, Am7 and Am7♭5 all use it.
• Major 7th: one fret below the root’s octave. Only maj7 chords use it.

So if you can find the octave of the root in a shape, you can turn it into a 7th chord by moving that note down one or two frets. This is how most open 7th shapes are made: E7 is E with the D-string octave lifted to open D, and C7 is C with an extra B♭ on the G string, fret 3.

The 7th chords in a key

Stack one more 3rd on each chord of a major key and you get its 7th chords. The pattern of types is the same in every major key: maj7, m7, m7, maj7, 7, m7, m7♭5.

In G major that is Gmaj7, Am7, Bm7, Cmaj7, D7, Em7, F♯m7♭5. In C major it is Cmaj7, Dm7, Em7, Fmaj7, G7, Am7, Bm7♭5.

Two things follow. There is only one dominant 7th in a major key, on the V chord, which is why D7 sounds like it leads to G. And the half-diminished chord sits on the 7th degree, the same place as the diminished triad. The key of G major page plays all of these with audio.

Where each type is used

• Dominant 7th (7): the V chord pulling back home, and the sound of the blues, where every chord is often a 7th. More in what is a dominant 7th chord.
• Major 7th (maj7): a soft, open colour on the I and IV chords. Common in jazz, bossa nova, soul and soft pop; open Cmaj7 is the easiest one to start with.
• Minor 7th (m7): the ii, iii and vi chords of a major key; smoother than a plain minor chord. See what is a minor 7th chord.
• Half-diminished (m7♭5): the vii chord in major and the ii chord in minor, as in Bm7♭5, E7, Am. See half-diminished 7th chords.
• Diminished 7th (dim7): a passing chord that links two chords a whole step apart, such as C, C♯dim7, Dm.

Common open 7th chord shapes

These are the 7th chords that need no barre. The six dominant 7ths are part of the basic cowboy chord set.

Fmaj7 is also the usual first step toward F: it is the easy F shape with the high e string left open.

How to read 7th chord names

A 9, 11 or 13 chord with no “maj” or “m” in its name, such as G9 or G13, is a dominant 7th with more notes stacked on top. G9 still has the F of G7; it just adds A.