Seventh chords and extensions

Triads have three notes. Add one more third on top and you get a seventh chord — a richer, more colorful sound used in jazz, blues, soul, funk, bossa nova and plenty of rock.

The main seventh chords

Chord	Symbol	Formula	Sound
Major 7th	Cmaj7	1 – 3 – 5 – 7	Dreamy, soft, sophisticated
Dominant 7th	C7	1 – 3 – 5 – ♭7	Bluesy, tense, wants to resolve
Minor 7th	Cm7	1 – ♭3 – 5 – ♭7	Mellow, smooth, soulful
Half-diminished	Cm7♭5	1 – ♭3 – ♭5 – ♭7	Dark, unresolved
Diminished 7th	Cdim7	1 – ♭3 – ♭5 – 𝄫7	Dramatic, suspenseful

Click each chord to hear it:

Seventh chords in a key

Stacking four notes on each degree of C major gives:

I	ii	iii	IV	V	vi	vii
Cmaj7	Dm7	Em7	Fmaj7	G7	Am7	Bm7♭5

The V7 chord is the only dominant 7th in a major key — that's why it creates such a strong pull back to I.

The ii – V – I

The most important progression in jazz uses seventh chords:

Dm7 → G7 → Cmaj7 → Cmaj7 · 80 BPMPlay

↓1

·&

↓2

·&

↓3

·&

↓4

·&

And here's the same idea with a soulful minor feel:

Am7 → Dm7 → Em7 → Am7 · 85 BPMPlay

↓1

·&

↓2

↑&

·3

↑&

↓4

↑&

Movable seventh chord shapes

Like barre chords, seventh chords have E-shape (root on the 6th string) and A-shape (root on the 5th string) versions. Find them all in the chord dictionary — for example C7, Am7 and Gmaj7.

Extensions and color chords

Keep stacking thirds past the 7th and you get extensions: 9, 11 and 13. You don't need to master them now, but here are a few colorful chords you'll meet often:

• add9 — a triad plus the 9th (the 2nd, an octave up). Bright and open. Very common in pop and rock ballads.
• 9 — a dominant 7th plus the 9th. The funk and soul chord.
• 6 — a major triad plus the 6th. A vintage, sweet sound.
• sus2 / sus4 — the third replaced by the 2nd or 4th.