Intervals
Perfect Fourth
4P · 5 semitones
Five semitones — stable, open, and the interval a bass line moves by more than any other.
Also written P4 · 4P
Perfect Fourth
4P · 5 semitones
On the piano, from every note
| From | Notes | Play it on your instrument |
|---|---|---|
| C | C – F | |
| C# | C# – F# | |
| D | D – G | |
| Eb | Eb – Ab | |
| E | E – A | |
| F | F – Bb | |
| F# | F# – B | |
| G | G – C | |
| Ab | Ab – Db | |
| A | A – D | |
| Bb | Bb – Eb | |
| B | B – E |
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.
Hear it in music
Songs that open with Perfect Fourth: the first two notes of each are the interval, which is how most players learn to recognise it.
Here Comes the BrideWagner
The opening leap is a perfect fourth.
Amazing GraceTraditional
The first two notes rise a perfect fourth.
Auld Lang SyneTraditional
The opening interval.
Scales that contain it
C MajorC · D · E · F · G · A · B
C MinorC · D · Eb · F · G · Ab · Bb
C Harmonic MinorC · D · Eb · F · G · Ab · B
C Melodic MinorC · D · Eb · F · G · A · B
C DorianC · D · Eb · F · G · A · Bb
C PhrygianC · Db · Eb · F · G · Ab · Bb
C MixolydianC · D · E · F · G · A · Bb
C LocrianC · Db · Eb · F · Gb · Ab · Bb
C Minor PentatonicC · Eb · F · G · Bb
C Minor BluesC · Eb · F · Gb · G · Bb
C ChromaticC · Db · D · Eb · E · F · Gb · G · Ab · A · Bb · B
C Phrygian DominantC · Db · E · F · G · Ab · Bb
C Harmonic MajorC · D · E · F · G · Ab · B
In C major
- C–F
- D–G
- E–A
- G–C
- A–D
- B–E
Understanding Perfect Fourth
Names and symbols
Perfect Fourth is written P4, 4P: 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 perfect fourth spans 5 semitones: C – F. It is a consonance, but an ambiguous one: played above a bass note it sounds settled, and played as the lowest interval of a chord it sounds unresolved, wanting to fall to a third.
That double life is why counterpoint treats the fourth as a dissonance against the bass and a consonance everywhere else — the same interval, judged by where it sits.
How composers use it
Root motion by fourths is the strongest progression in tonal music: V to I is a fourth up, and the circle of fifths read backwards is a chain of them. Stacked fourths give the quartal voicings of McCoy Tyner and of a great deal of modern film writing.
It is also how most of the guitar is tuned — four of the five string pairs are a perfect fourth apart, which is why so many shapes transpose unchanged across the neck. Its inversion is the Perfect Fifth.
Learn this properly
Chapter 5: IntervalsCommon questions
- How many semitones is a Perfect Fourth?
- A Perfect Fourth spans 5 semitones: C – F. Count the semitones of any interval with the interval calculator.
- Why is the perfect fourth sometimes called a dissonance?
- In strict counterpoint a fourth above the bass is treated as a dissonance needing resolution. Between upper voices it is a consonance. The rule is about position, not sound.
- What is the inversion of a perfect fourth?
- The Perfect Fifth. Perfect intervals invert to perfect intervals.
- How do I play Perfect Fourth?
- On guitar the handiest shape is Next string, B 1 · E 1, read as string and fret; the instrument panel draws it from any starting note with the other shapes. On the piano count 5 semitones up from any key, black keys included. Play the notes together for the harmonic form, one after the other for the melodic form.