Seventh Chords: A Complete Guide to maj7, min7, dom7, and More

If triads are the foundation of harmony, seventh chords are where music starts to get truly expressive. By adding just one more note on top of a triad, you unlock a world of colour, tension, and sophistication that has shaped everything from classical sonatas to jazz standards, R&B ballads, and lo-fi beats.

This guide walks you through every common type of seventh chord, how each one is built, where it naturally occurs, and what gives it its distinctive sound.

What Is a Seventh Chord?

A seventh chord is a four-note chord formed by stacking an additional third on top of a triad. Where a triad contains a root, third, and fifth, a seventh chord adds the seventh — the note that sits a seventh interval above the root.

Because there are different qualities of triads (major, minor, diminished, augmented) and different qualities of sevenths (major seventh, minor seventh), several distinct seventh chord types emerge when you combine them.

Major Seventh (maj7)

Formula: 1 – 3 – 5 – 7

A major seventh chord pairs a major triad with a major seventh interval. The result is warm, lush, and dreamy — a sound often described as “sophisticated” or “bittersweet.”

Example — Cmaj7: C – E – G – B

The major seventh interval (the distance from C to B, eleven semitones) creates a gentle dissonance that resolves beautifully within the chord itself. You will hear maj7 chords everywhere in jazz, bossa nova, neo-soul, and city pop.

In diatonic harmony, maj7 chords appear naturally on the I and IV degrees of a major scale. In the key of C major, that gives you Cmaj7 (I) and Fmaj7 (IV).

Minor Seventh (min7 or m7)

Formula: 1 – ♭3 – 5 – ♭7

A minor seventh chord combines a minor triad with a minor seventh interval. It sounds mellow, smooth, and slightly melancholic — a staple of soul, R&B, funk, and jazz.

Example — Dm7: D – F – A – C

Minor seventh chords feel relaxed and open. They lack the sharp tension of dominant chords and the brightness of major sevenths, settling into a comfortable middle ground that works beautifully in extended progressions.

In a major key, m7 chords appear on the ii, iii, and vi degrees. In C major: Dm7 (ii), Em7 (iii), and Am7 (vi).

Dominant Seventh (dom7 or just “7”)

Formula: 1 – 3 – 5 – ♭7

The dominant seventh chord is arguably the most important seventh chord in all of Western music. It combines a major triad with a minor seventh, creating a built-in tension that wants to resolve.

Example — G7: G – B – D – F

That tension comes from the tritone — the interval between the third (B) and the flat seventh (F). This tritone is inherently unstable, and it pulls strongly toward resolution, usually to the I chord. The V7-to-I resolution is the backbone of tonal music.

In diatonic harmony, the dominant seventh appears naturally on the V degree. In C major, that is G7. But dominant sevenths are also used freely outside their diatonic position — in blues, every chord can be a dominant seventh, and secondary dominants borrow this tension to tonicize other scale degrees.

Half-Diminished Seventh (m7♭5 or ø7)

Formula: 1 – ♭3 – ♭5 – ♭7

The half-diminished seventh chord (also written as m7♭5) combines a diminished triad with a minor seventh. It has an uneasy, questioning quality — not as harsh as a fully diminished chord, but distinctly tense and unresolved.

Example — Bm7♭5 (Bø7): B – D – F – A

This chord appears naturally on the vii degree of a major key (Bm7♭5 in C major) and on the ii degree of a minor key (Dm7♭5 in C minor). In jazz, the half-diminished chord is essential in minor ii-V-i progressions, where it serves as the ii chord leading to a dominant and then to a minor tonic.

Fully Diminished Seventh (dim7 or °7)

Formula: 1 – ♭3 – ♭5 – ♭♭7 (double-flat 7, enharmonically a 6th)

The fully diminished seventh chord stacks a diminished triad with a diminished seventh interval. Every note is separated by exactly three semitones (a minor third), making it a perfectly symmetrical chord.

Example — Bdim7: B – D – F – A♭

Because of its symmetry, there are really only three unique diminished seventh chords — each one simply inverts into the others. Bdim7, Ddim7, Fdim7, and A♭dim7 all contain the same notes.

Diminished seventh chords sound dramatic, tense, and urgent. They have been a favourite device for creating suspense since the Baroque era and remain common in film scoring, classical music, and jazz as passing chords or substitutes for dominant sevenths.

Minor-Major Seventh (mM7 or m(maj7))

Formula: 1 – ♭3 – 5 – 7

This is the rarest of the common seventh chords. It combines a minor triad with a major seventh — a pairing that creates an intense, almost eerie dissonance.

Example — CmM7: C – E♭ – G – B

The clash between the minor third (E♭) and the major seventh (B) gives this chord a dark, mysterious, and slightly unsettling character. You will hear it in film noir soundtracks, certain tango compositions, and jazz ballads that want a haunting quality.

The minor-major seventh appears naturally on the i degree of the harmonic minor scale. In C harmonic minor (C – D – E♭ – F – G – A♭ – B), the tonic chord built in sevenths is CmM7.

Seventh Chords in Diatonic Harmony

When you build seventh chords on every degree of the C major scale, you get this sequence:

Degree	Chord	Type
I	Cmaj7	Major 7th
ii	Dm7	Minor 7th
iii	Em7	Minor 7th
IV	Fmaj7	Major 7th
V	G7	Dominant 7th
vi	Am7	Minor 7th
vii°	Bm7♭5	Half-diminished

This pattern — maj7, m7, m7, maj7, dom7, m7, m7♭5 — holds true in every major key. Memorise it, and you will always know which seventh chord type belongs to which scale degree.

The Characteristic Sound of Each Type

A helpful way to internalise seventh chords is to think about where each one sits on a spectrum from bright to dark:

Major 7th — Bright, warm, dreamy
Dominant 7th — Bright but tense, wants to move
Minor 7th — Mellow, smooth, relaxed
Minor-major 7th — Dark, mysterious, haunting
Half-diminished — Uneasy, questioning, unstable
Fully diminished — Dramatic, urgent, symmetrical tension

Try playing each type with the same root note — say, all built on C — and listen to how the mood shifts with just one or two altered notes. An Interactive Chord Finder tool is perfect for this kind of exploration, letting you hear and see the note differences side by side.

Putting Seventh Chords Into Practice

Start by revisiting songs and progressions you already know, but replace the basic triads with their diatonic seventh chord equivalents. A simple I–vi–IV–V in C major becomes Cmaj7–Am7–Fmaj7–G7, and the harmonic richness transforms immediately.

From there, experiment with non-diatonic seventh chords. Try a dominant seventh on the II degree (a secondary dominant) or slip a diminished seventh chord between two diatonic chords as a chromatic passing chord.

Seventh chords are the gateway to jazz harmony, extended chords, and altered voicings. Once you hear and understand the six types covered here, you have the vocabulary to explore virtually any harmonic territory you choose.