Music intervals: hear every gap in one table

Every interval, one table: from Jaws to Star Wars

An interval is the distance between two notes. It is the atom of music theory: intervals are what make a chord major or minor, what give a melody its character, and what ear training is actually training. The table below covers all 13 intervals in Western music. For each one you get the semitone count, an ascending and descending song cue to fix it in your ear, its sound character, and where it appears in everyday chords. All in one place, no hunting across separate articles.

How to use this for ear training

Pick one interval per week. Find your ascending and descending song cue above. When you hear those two notes anywhere, name the interval before you think about it. That reflex is what ear training builds. The intervals divide into three families by feel: Consonant and stable: unison, octave, perfect 5th, perfect 4th. These resolve the tension in a phrase. The 4th has a slight upward yearning but still sounds settled. Mildly consonant: major and minor 3rds, major and minor 6ths. These are the intervals that colour a chord as happy or sad. The 3rds give a triad its quality; the 6ths add warmth. Dissonant and tense: minor 2nd, major 2nd (mildly), tritone, minor 7th, major 7th. These intervals push toward resolution. The tritone is the most extreme: six semitones in both directions from the octave, equidistant from everything, unstable in any context.

The tritone: why it was called the devil in music

The tritone (six semitones, also written as an augmented 4th or diminished 5th) was labelled "diabolus in musica" by medieval theorists who banned its use in sacred composition. The ban stuck partly because the interval genuinely does sound unresolved: it splits the octave exactly in half, so it has no natural pull toward either the note above or the note below. In modern harmony the tritone is the tension engine inside every dominant 7th chord. In a G7 chord, the notes B and F form a tritone. When G7 resolves to C major, the B moves up a semitone to C and the F moves down a semitone to E. That semitone voice-leading in opposite directions is what makes the resolution feel satisfying. Remove the tritone and the dominant chord loses its urgency. The Simpsons theme is the most cited ear-training mnemonic because the ascending tritone in "Simp-sons" is instantly recognisable and used in an ascending direction, which is the rarer way tritones appear in melodies.

Perfect intervals: why the name

Unison, octave, perfect 4th, and perfect 5th are called "perfect" because they were considered pure in medieval tuning systems: their frequency ratios are simple fractions (2:1 for the octave, 3:2 for the 5th, 4:3 for the 4th). They cannot be made major or minor, only augmented or diminished. The 5th is the foundation of Western harmony. Stack two 5ths and you get the outline of a major chord. Stack twelve 5ths and you traverse all 12 notes of the chromatic scale (the circle of fifths). Every guitar power chord is a root plus a 5th, stripped of the 3rd that would make it major or minor.

How intervals build chords