What is an Interval?

An interval is a combination of two notes or a distance between two notes. Intervals are always counted from the lower note to the higher one. If the two notes of an interval are sounded in succession it is described as a melodic interval. If sounded simultaneously, then it is a harmonic interval.

Melodic IntervalHarmonic Interval

What do Intervals look like on the Piano Keyboard?

In Western music the shortest distance between two notes is a half tone (or semitone). This distance could be seen on a piano keyboard between a consecutive white and black key as well as between the white notes E and F, and B and C.   A whole tone is the distance between notes that is equal to two half tones.

Half Tone (Semitone)Whole Tone (Tone)

Qualities and Sizes of Intervals

Intervals can be described as Major , Minor , Perfect , Augmented , and Diminished. These are characteristics of the interval’s quality. Besides, each interval has its own size: Unison, Second, Third, Fourth, Fifth, Sixth, Seventh, Octave. For example, Minor Third is a name of an interval where Minor indicates its quality and Third is a size.

  • Unison
  • Minor Second = half none
  • Major Second = whole tone
  • Minor Third = whole tone + half tone (3 half tones)
  • Major Third = 2 whole tones (4 half tones)
  • Perfect Fourth = 2 whole tones + 1 half tone ( 5 half tones)
  • Augmented Fourth = 3 whole tones (6 half tones) (tritone)
  • Diminished Fifth = 3 whole tones (6 half tones)  (tritone)
  • Perfect Fifth = 3 whole tones + 1 half tone (7 half tones)
  • Minor Sixth = 4 whole tones (8 half tones)
  • Major Sixth = 4 whole tones + 1 half tone (9 half tones)
  • Minor Seventh = 5 whole tones (10 half tones)
  • Major Seventh = 5 whole tones + 1 half tone (11 half tones)
  • Perfect Octave = 6 whole tones (12 half tones)

Different Spellings of Intervals

Sometimes two intervals contain the same number of intervals or the same pitch spelled in different ways. For example, C – F sharp (Augmented Fourth) is equivalent to C – G flat (Diminished Fifth) but named differently. Because C-D-E-F (interval contains 4 notes) is a Fourth and F sharp means that the higher note of the interval is augmented, and C-D-E-F-G (Interval contains 5 notes) is a Fifth and G flat means that the higher note of the interval is diminished.

The Tritone

Tritone is an interval composed of three whole tones or six half tones. It occurs:

  • in diatonic scales.

In Major scale a tritone (augmented fourth) occurs naturally between 4th and 7th scale degrees. In Natural Minor a tritone forms between 2nd and 6th scale degrees; in Melodic Minor when the scale ascends, the tritone appears between the 3rd and 6th scale degrees and the 4th and 7th scale degrees, and when the scale descends, the tritone appears between the 2nd and 6th scale degrees.

C Major

C Major


A Minor (Natural)

 A Minor (Natural)


A Minor Melodic

A Minor (Melodic)


  • in chromatic scales: 6 augmented fourths and 6 diminished fifths.
  • in chords. Some chords e.g. the dominant seventh chord, the diminished chord, the half diminished seventh chord, the fully diminished seventh chord, the augmented sixth chords include augmented fourths or diminished fifths.

Inversion of Intervals

All intervals can be inverted. The lower note is raised up an octave so that the top note/bottom note relationship is reversed. The chart below shows intervals and their inversions.

Intervals and Their Inversions