Intervals
Diminished Fourth
4d · 4 semitones
A fourth narrowed to the width of a major third, produced by chromatic voice leading.
Also written d4 · 4d
Diminished Fourth
4d · 4 semitones
On the piano, from every note
| From | Notes | Play it on your instrument |
|---|---|---|
| C | C – Fb | |
| C# | C# – F | |
| D | D – Gb | |
| Eb | Eb – Abb | |
| E | E – Ab | |
| F | F – Bbb | |
| F# | F# – Bb | |
| G | G – Cb | |
| Ab | Ab – Dbb | |
| A | A – Db | |
| Bb | Bb – Ebb | |
| B | B – Eb |
Tap a key or a fret to hear it.
Read on: number and quality · inversion · compound intervals · consonance and dissonance
Every fourth
A fourth can take these qualities, one semitone apart; choose one to see the upper note move and hear the pair.
Understanding Diminished Fourth
Names and symbols
Diminished Fourth is written d4, 4d: the letter is the quality, the number the size. Chord formulas on this site write the number first, as tonal does.
"Perfect" is not praise. Unisons, fourths, fifths and octaves take the qualities perfect, augmented and diminished, never major or minor, because their inversions keep the same quality. A fourth one semitone narrower than perfect is diminished, not minor.
How it sounds
A diminished fourth spans 4 semitones: C – Fb. The ear hears a major third; the page says fourth, because both notes are acting as degrees a fourth apart.
Where it comes from
It turns up in harmonic minor, between the raised seventh degree and the third above it, and in any passage where a leading tone is held against a flattened upper note. It is a hallmark of late-Romantic chromaticism.
Learn this properly
Chapter 5: IntervalsCommon questions
- How many semitones is a Diminished Fourth?
- Four — C – Fb — the same distance as a major third. Count the semitones of any interval with the interval calculator.
- Where does a diminished fourth occur naturally?
- In the harmonic minor scale, between the raised seventh and the third degree above it.
- What is its inversion?
- The Augmented Fifth.
- How do I play Diminished Fourth?
- On guitar the handiest shape is Next string, B 1 · E 0, read as string and fret; the instrument panel draws it from any starting note with the other shapes. On the piano count 4 semitones up from any key, black keys included. Play the notes together for the harmonic form, one after the other for the melodic form.
- What is the inversion of Diminished Fourth?
- The inversion of Diminished Fourth is the Augmented Fifth: put the lower note an octave higher and the distance that remains is the inversion. The two always add up to an octave, 4 semitones and 8 semitones, and swap their qualities between major and minor, or keep perfect as perfect.