Seventh Chords

A seventh chord is a triad with one more 3rd on top: a root, 3rd, 5th and 7th. G–B–D–F is G7. Its name comes from the triad underneath and the 7th above the root, which gives five types: major seventh, dominant seventh, minor seventh, half-diminished and diminished seventh.

By Dan Vrancic, music theory teacher · Reviewed October 2026

What is a seventh chord?

A triad stacks two 3rds. Add a third 3rd and you have a four-note chord: a seventh chord, named for its top note, a 7th above the root. From G, skip a letter three times: G, B, D, F. The four notes are the root, 3rd, 5th and 7th, and on the staff they sit on four lines or four spaces in a row.

G–B–D–F: root, 3rd, 5th and 7th, each a 3rd above the last.

The five types of seventh chord

Each seventh chord is a triad plus a 7th. Build them all on C and only one note changes from each chord to the next.

NameSymbol on CTriad7thNotes
Major seventhCmaj7majorMajor 7thC–E–G–B
Dominant seventhC7majorminor 7thC–E–G–B♭
Minor seventhCm7minorminor 7thC–E♭–G–B♭
Half-diminishedCm7♭5 (Cø7)diminishedminor 7thC–E♭–G♭–B♭
Diminished seventhC°7diminisheddiminished 7thC–E♭–G♭–B♭♭
Each chord lowers one note of the chord before it.

The diminished seventh's top note, B♭♭ (B double flat), is played on the A key but written on B, because a 7th above C always uses the letter B.

The dominant seventh

The dominant seventh is a major triad with a minor 7th. Built on degree 5 of C major it is G–B–D–F, written G7, or V7 in the key. It is the most common seventh chord.

Its 3rd and 7th, B and F, are six semitones apart: a tritone. That tension wants to resolve. B rises a semitone to C and F falls a semitone to E, landing on the tonic chord.

G7 to C: the tritone B–F resolves inward to C–E.

How to name a seventh chord

  1. Name the triad

    Cover the top note and name the triad that is left: major, minor or diminished.

  2. Measure the 7th

    Find the 7th of the root's major scale. The same note: Major 7th. One semitone lower: minor 7th. Two semitones lower: diminished 7th.

  3. Put them together

    Use the table: a diminished triad with a minor 7th is half-diminished.
D–F–A♭ is a diminished triad. D major's 7th is C♯, and C is a semitone lower: a minor 7th. So the chord is half-diminished.

Seventh chords in a key

Stack four notes of a key on each scale degree and you get its seven diatonic seventh chords. Every major key has the same pattern.

DegreeNumeralSeventh chordIn C major
1Imaj7major seventhCmaj7
2ii7minor seventhDm7
3iii7minor seventhEm7
4IVmaj7major seventhFmaj7
5V7dominant seventhG7
6vi7minor seventhAm7
7viiø7half-diminishedBm7♭5
The seven diatonic seventh chords of C major.

Only V gets a minor 7th above a major triad, so V7 is the key's one dominant seventh. ii7–V7–Imaj7 (Dm7–G7–Cmaj7 in C major) is the most common seventh-chord progression of all.

In a minor key, music usually raises the 7th note, which makes the chord on 5 a dominant seventh and the chord on 7 fully diminished. In A minor: Am7, Bm7♭5, Cmaj7, Dm7, E7, Fmaj7 and G♯°7.

Try it: name the seventh chord

Chord 1 of 6

G–B–D–F: what kind of seventh chord is it?

See it step by step

The interactive explainer from Lesson 21, with sound. Step through it at your own pace.

Practice on paper

Free printable worksheets on this topic, each with an answer key.

Seventh chord worksheets with answer keys

Questions about seventh chords

What is a seventh chord?
A four-note chord built in 3rds: a triad with one more 3rd on top. The top note is a 7th above the root, which gives the chord its name. G–B–D–F is a G seventh chord.
What are the five types of seventh chords?
Major seventh (major triad, Major 7th), dominant seventh (major triad, minor 7th), minor seventh (minor triad, minor 7th), half-diminished (diminished triad, minor 7th) and diminished seventh (diminished triad, diminished 7th).
What is the difference between Cmaj7 and C7?
Both have a C major triad. Cmaj7 adds a Major 7th, B, so it sounds settled. C7 adds a minor 7th, B♭, which makes it a dominant seventh that pulls toward F.
What is a dominant seventh chord?
A major triad with a minor 7th, such as G–B–D–F (G7). It is built on the 5th degree of a major key, written V7, and its 3rd and 7th form a tritone that resolves to the tonic chord.
What is a half-diminished seventh chord?
A diminished triad with a minor 7th, such as B–D–F–A. It is written Bm7♭5 or Bø7, and it is the seventh chord on the 7th degree of a major key.
What is the difference between half-diminished and fully diminished?
Both have a diminished triad. Half-diminished adds a minor 7th (C–E♭–G♭–B♭); a fully diminished seventh lowers that 7th once more (C–E♭–G♭–B♭♭), so every 3rd in the chord is minor.
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.

Members get · Rankings

See where you rank

Your Theory Tempo climbs from Grave to Prestissimo as you get faster, and every sprint shows how you compare with other players.

Practice that never runs out. Fresh questions on seventh chords every time, checked the moment you answer. What you miss comes back until it sticks.

See all features See plans

In the course: Lesson 21: Types of Seventh Chords, Lesson 22: Diatonic Seventh Chords