What are seventh chords?
A triad stacks two thirds on a root. A seventh chord adds a third one, so it has four notes: the root, third, fifth and seventh. That extra note is the source of their richness. There are several kinds, and the main ones differ by only one note.
| Chord | Formula | Notes on C | Sounds |
|---|---|---|---|
| Cmaj7major 7th | 1 3 5 7 | C E G B | smooth, warm and dreamy |
| C7dominant 7th | 1 3 5 ♭7 | C E G B♭ | bluesy and tense, wanting to resolve |
| Cm7minor 7th | 1 ♭3 5 ♭7 | C E♭ G B♭ | mellow and soulful |
| Cø7half-diminished | 1 ♭3 ♭5 ♭7 | C E♭ G♭ B♭ | dark and bittersweet |
| C°7diminished 7th | 1 ♭3 ♭5 𝄫7 | C E♭ G♭ B𝄫 | dramatic and very unstable |
| Cm(maj7)minor-major 7th | 1 ♭3 5 7 | C E♭ G B | dramatic and mysterious, like a film noir |
| C7♯5augmented 7th | 1 3 ♯5 ♭7 | C E G♯ B♭ | tense with a wobble |
Look at the formulas. Start at Cmaj7 (C E G B). Lower the B a half step to B♭ and it becomes C7. Lower the E as well and it is Cm7. Lower the G too and it is Cm7♭5. Each step is one note moving down by a half step.
The five you need most
Major 7th (maj7)
A major triad plus a major seventh. Smooth, warm and a bit wistful. It makes a good I or IV chord in jazz, bossa nova, soul and ballads, anywhere a plain major chord feels too plain. Try Cmaj7 → Fmaj7.
Dominant 7th (7)
A major triad plus a minor seventh. The sound of blues, and the V chord of a key: G7 → C is the strongest resolution in tonal music. The tritone between its third and seventh (B and F in G7) is what creates the pull.
Minor 7th (m7)
A minor triad plus a minor seventh. Mellow and relaxed, the standard minor chord in jazz, R&B and soul. In a major key it is the chord on the 2nd, 3rd and 6th degrees. Dm7 → G7 → Cmaj7 is the most important progression in jazz (ii-V-I).
Half-diminished (m7♭5 or ø7)
A diminished triad plus a minor seventh. It is the ii chord in a minor key: Bm7♭5 → E7 → Am (ii-V-i). Dark and bittersweet.
Diminished 7th (°7)
A diminished triad plus a diminished seventh: four notes, all minor thirds apart. Unstable, dramatic, and often a passing chord. Because it is symmetrical, it can be named from any of its four notes.
Seventh chords in a key
Every note of the major scale can carry a seventh chord. In C major: Cmaj7, Dm7, Em7, Fmaj7, G7, Am7, Bm7♭5. The pattern is always the same: maj7, m7, m7, maj7, 7, m7, m7♭5. Learn the pattern and you know them in every key. The chords in every key chart shows the full table.
How to use seventh chords effectively
- Colour a plain progression. Swap the I chord for Imaj7 and the vi for vi7 and a simple progression sounds more refined.
- Use V7 for a strong ending. Reserve the dominant 7th for the V chord and let it resolve to give a real sense of coming home.
- Mind the style. A dominant 7 on every chord is blues. Maj7 and m7 everywhere is jazz and soul. Plain triads with the occasional seventh is folk and pop.
- Leave notes out. On guitar, drop the fifth. On piano, keep the third and seventh and let the bass play the root.
How to practise
- Warm-up: dominant 7, major 7 and minor 7 on white-key roots, with the note names on the keys. Look at what happens to the seventh and the third.
- Working set: every root, with half-diminished added. You also build chords by tapping the keys.
- Heavy lift: dim7, minor-major 7 and augmented 7, shown in inversions.
After this, learn the sixth and ninth chords, which are built on these. If seventh chords are new, the chord types guide shows where they fit. Shapes for guitar and ukulele are in the chord library, and you can practise their inversions with the inversion trainer.
Frequently asked questions
What is a seventh chord?
A triad with a fourth note added, a seventh above the root. Stack another third on top of a triad and you get a seventh chord. The type of seventh and the type of triad determine the flavour.
What is the difference between maj7 and dominant 7?
Both are a major triad with a seventh on top. The major 7th chord (C E G B) uses the major seventh, a half step below the octave, and sounds smooth and dreamy. The dominant 7th (C E G B♭) uses the minor seventh, a whole step below the octave, and sounds bluesy and tense.
Why is it called a dominant 7th?
It is the seventh chord that naturally occurs on the dominant (V) of a major key, such as G7 in C major. Its tension pulls strongly to the tonic, which is what dominant chords do.
What does m7 mean?
A minor seventh chord: a minor triad with a minor seventh (C E♭ G B♭). It is mellow and soulful, and the ii, iii and vi chords in a major key are all minor 7ths when you add sevenths.
What are the seventh chords in a major key?
Imaj7, ii7, iii7, IVmaj7, V7, vi7 and viiø7. In C major: Cmaj7, Dm7, Em7, Fmaj7, G7, Am7 and Bm7♭5.
What is a half-diminished chord?
A diminished triad with a minor seventh, also written m7♭5 or ø7 (C E♭ G♭ B♭). It is the ii chord in a minor key and the vii chord in a major key.
Do I have to play all four notes?
Not always. On guitar you often leave out the fifth. On piano you can leave out the root when a bass player has it. The third and seventh carry most of the character, so keep those.
What is the easiest way to learn them?
Take the triad you know and change one note: lower the seventh from major to minor to turn maj7 into a dominant 7, or flatten the third to turn a dominant 7 into a minor 7. The drill gets you to hear and see those one-note changes.