Seventh Chords Explained: Major, Dominant, Minor and Half-Diminished Sevenths

A seventh chord adds one more third on top of a triad, producing four notes instead of three. The extra note changes the color of the chord, making it sound richer, more tense or more restless depending on its type. Seventh chords are central to jazz, blues, gospel and classical harmony, and learning their construction gives you a clear way to read most chord symbols you will meet. This guide covers the common types, their semitone patterns and how to spell them correctly.

From triad to seventh

A seventh chord starts from a triad and adds a note a third above the fifth. The seventh is the interval of a seventh above the root, which is either major, eleven semitones above the root, or minor, ten semitones above the root. The name of the chord comes from this seventh, so a chord with a minor seventh above the root is a seventh chord rather than a major chord with an added note.

Because each added note is a third, the seventh chord is still a tertian chord built by stacking thirds. The only new interval to learn is the seventh, and the quality of the seventh changes the chord's character.

The four common types

The four most common seventh chords are the major seventh, the dominant seventh, the minor seventh and the half-diminished seventh. Each one combines a triad quality with a seventh quality. The table below shows the semitone patterns from the root.

Chord type	Triad	Seventh	Semitones from root	Example on C
Major seventh	Major	Major	0, 4, 7, 11	C E G B
Dominant seventh	Major	Minor	0, 4, 7, 10	C E G B flat
Minor seventh	Minor	Minor	0, 3, 7, 10	C E flat G B flat
Half-diminished	Diminished	Minor	0, 3, 6, 10	C E flat G flat B flat

The dominant seventh has a major triad with a minor seventh, which is the most common chord in tonal music. The half-diminished seventh is also called the minor seven flat five, and the fully diminished seventh is a separate type with three minor thirds stacked on top of each other.

The major seventh

The major seventh chord has a major triad with a major seventh above the root. In C, the chord is C, E, G and B. The major seventh sounds bright and smooth, and it is common in jazz ballads and in pop harmony that wants a soft, floating color. The major seventh is one semitone below the octave, which makes it sound close to the root and gives the chord its dreamy character.

The dominant seventh

The dominant seventh chord has a major triad with a minor seventh above the root. In C, the chord is C, E, G and B flat. The tritone between E and B flat is the most important sound in the chord, because that interval strongly pulls toward resolution. The dominant seventh on the fifth degree usually resolves to the tonic chord, which is why it is central to cadences.

Blues and rock use dominant sevenths for their characteristic tension. Many blues progressions use the dominant seventh on every chord, which gives the music its restless, driving sound.

The minor seventh

The minor seventh chord has a minor triad with a minor seventh above the root. In C minor seventh, the notes are C, E flat, G and B flat. This chord is soft and mellow, and it often appears on the second, third and sixth degrees of a major key. It is a staple of jazz, soul and R&B progressions because it blends well with melody.

The half-diminished seventh

The half-diminished seventh chord has a diminished triad with a minor seventh above the root. In B, the notes are B, D, F and A. The chord is named half-diminished because it contains a diminished fifth but keeps the minor seventh rather than the fully diminished seventh. It usually sounds dark and unstable, and it often appears on the seventh degree of a major key or on the second degree of a minor key.

Spelling seventh chords

Spelling works the same way as for triads. Write the four letter names in order, starting from the root and adding thirds, then adjust accidentals until the semitone pattern matches the chord type. A C major seventh must use B natural, not C flat, because the seventh is the letter name seven steps above C. A B half-diminished seventh uses D, F and A, which are the letters above B in thirds.

A common mistake is to write the right sound with the wrong letter name, such as A sharp in place of B flat. The chord may sound correct on a keyboard, but a reader cannot see its function on the staff, so always check the letter names before writing the chord.

Inversions and voicings

In Roman numeral analysis, a seventh chord is marked with a 7 after its numeral, so a dominant seventh on the fifth degree is written V7. Figured bass uses 7 for root position, 6/5 for first inversion, 4/3 for second inversion and 4/2 for third inversion. These figures let you read the chord type straight from a bass line.

Seventh chords can be inverted like triads, with the third, fifth or seventh in the bass. Each inversion has its own sound and its own role in a progression. In practice, pianists and guitarists often leave out the fifth, which keeps the chord clear and reduces the number of notes they must play. Open and closed voicings also change the sound, because spreading the notes across more octaves produces a fuller texture.

Practice routine

Build each seventh type on C, F, G and B flat. Start with the triad, then add the seventh and check the semitone count. Play the dominant seventh and resolve it to the tonic, listening for the pull created by the tritone. Then play the major seventh and the minor seventh in the same progression to compare how the seventh changes the color.

Record yourself playing a short progression that moves through all four types. Listening back helps you hear which chords lean toward rest and which lean toward motion.

Key takeaways

A seventh chord adds a third above a triad, and the quality of that seventh defines the chord type. The four common types are major seventh, dominant seventh, minor seventh and half-diminished seventh.

Each type has a specific semitone pattern. The dominant seventh is the most important for cadences, because its tritone pulls toward the tonic.

Spell seventh chords by letter name first, then check the semitone counts. Practice the four types in several keys and listen for how each one changes the mood of a progression.