What Is An Interval in Music?
An interval is the distance between two notes, it is labelled by a number and a quality. Intervals can be harmonic and melodic.
A harmonic interval is when two notes are played together whereas the notes of a melodic interval are played successively.

What is Interval Quality?
There are five qualities of intervals namely :
- Perfect (P).
- Minor (m or b).
- Major (M or sometimes represented by a triangle ∆).
- Diminished (dim. or bb).
- Augmented (aug. or #).
What is Interval Number?
An interval number represent the position of a note from the root/tonic (R/1) or any other note. These numbers are : 1 (unisson), 2 (second), 3 (third), 4, (fourth), 5 (fifth), 6 (sixth), 7 (seventh), 8 (octave).
Exemple : E is the third of C (the third note after C), G is the fifth, etc. This intervals are called "simple intervals".
It is possible to count past 8, this is what we call compound intervals, they span more than one octave :
- 9 (ninth) actually second + octave.
- 10 (tenth) third + octave.
- 11 (eleventh) fourth + octave.
- 12 (twelfth) fifth + octave.
- 13 (thirteenth) six + octave.
Exemple, A is the thirteenth of C.
List of intervals - Simple and Compounds
Simple intervals :
You see that a second can be major (2) or minor (b2).
A third can be major (3) or minor (b3).
A fourth can be perfect (P4) or augmented (#4).
A fifth can be perfect (P5), diminished (b5) and augmented (#5).
A sixth can be minor (b6) or major (6).
A seventh can be minor (b7) or major (M7).
- 1 Unisson (Root).
- b2 or m2 - minor second - 1 semitone from the root.
- 2 or M2 or ∆2 - Major second - 2 semitones from the root.
- b3 or m3 - minor third - 3 semitones from the root.
- 3 or M3 or ∆3 - Major third - 4 semitones from the root.
- 4 or P4 - Perfect fourth - 5 semitones from the root.
- #4 or aug4 - Augmented fourth - 6 semitones from the root.
- b5 - or dim5 - Diminished fifth - 6 semitones from the root.
- 5 or P5 - Perfect fifth - 7 semitones from the root.
- #5 or aug5 - Augmented fifth - 8 semitones from the root.
- b6 or m6 - minor sixth - 8 semitones from the root.
- 6 or M6 or ∆6 - Major sixth - 9 semitones from the root.
- b7 or m7 - minor seventh - 10 semitones from the root.
- 7 or M7 or ∆7 - Major seventh - 11 semitones from the root.
- 8 or 8va - Octave - 12 semitones from the root.
Compound intervals :
The most used compound intervals are the b9, 9, #9, 11, #11, b13 and 13.
They are used to enrich / extand a chord or an arpeggio.
- b9 or m9 - minor ninth = Minor second plus an octave.
- 9 or Maj9 or ∆9 - Ninth = Major second plus an octave.
- #9, 9+ or aug9 - Augmented ninth = Augmented second plus an octave.
- 10 - Tenth = Major third plus an octave.
- 11 - Eleventh = Perfect fourth plus an octave.
- #11 - aug11 - Augmented eleventh = augmented fourth plus an octave.
- 12 - Twelfth = Perfect fifth plus an octave.
- b13 or min13 - Minor thirteenth = Minor sixth plus an octave.
- 13 - Thirteenth = Major sixth plus an octave.
Intervals On Guitar
Notes on the Guitar Neck
Here are two neck diagrams that will help you locate the notes on the guitar and give a name to the intervals.
The first shape includes sharp notes whereas the second shows the flat notes.