Quartal harmony
Quartal harmony is harmony whose chords are built from stacked fourths instead of thirds. Such chords are not stacked in thirds, therefore cannot be heard clearly as major or minor, and sound open, floating and without a clear key.
- Building block
- perfect fourth (5 semitones)
- Three-note chord
- e.g. C–F–B♭
- Four-note chord
- e.g. C–F–B♭–E♭
- In contrast to
- stacked thirds (major/minor)
- Used in
- 20th-century music, modern jazz
Fourths instead of thirds
The chords of classical harmony teaching are built from thirds. A triad consists of two, a seventh chord of three stacked thirds. Quartal harmony takes the perfect fourth as its building block. Three notes a fourth apart form a three-note chord of fourths, four a four-note one. Because the chord is not stacked in thirds, the decision between major and minor is suspended.
Three- and four-note chord from fourths
On the left three notes a fourth apart: C–F–B♭. On the right a fourth note above: E♭. Between the notes lie five semitones each. Between neighbouring notes there is always a fourth, never a third. Other intervals arise only between notes that are not neighbours: in the three-note chord between C and B♭ a minor seventh, in the four-note chord between C and E♭ a minor tenth (octave plus minor third). That is why the sound cannot be heard clearly as major or minor.
For comparison: stacked thirds
The same root, but built in thirds: the major triad and the major seventh chord. The difference lies in the middle of the sound, where the third is.
The same stacking of fourths, stepwise upwards
The same stacking of perfect fourths moves up the scale; on F it needs B♭ and E♭ for that. Because the structure stays the same, only the pitches change, not the character.
In the glossary: Parallel fourths · Suspended chord · Distance principle
| Stacked thirds | Stacked fourths | |
|---|---|---|
| Building block | third (3 or 4 semitones) | fourth (5 semitones) |
| Quality | major or minor | undetermined |
| Root | clear | mostly open |
| Sound | closed, functional | floating, modern |
Listening
The sound seems open and floating. It does not resolve but stays in place or moves on in parallel. Chords in fourths are widespread in modern jazz, for example with pianists such as McCoy Tyner, and occur in 20th-century music. The chord in fourths is related to the suspended chord (sus4), which also lacks the third.
Inversions
Because after inversion the fourth becomes a fifth, chords in fourths behave differently from chords in thirds: the inversion of a three-note chord of fourths is not a new position of the same chord but a different chord, in which fourths, a second and a fifth are mixed. C–F–B♭ inverted gives F–B♭–C, in which one note is a second from another.
Continue on Maikstrings
Related terms
Parallel fourthsSuspended chordPolychordTriadSeventh chordJazzDistance principleTetrachord
Editor: Maik Krohm · reviewed on 3 October 2026
← Back to the glossary