🎵 Music Theory

Music Intervals

Every interval name, distance, quality, and how to hear them

Explore Intervals on the Fretboard

Select an interval below to see it highlighted on the guitar neck (root on 6th string, 3rd fret = C).

Complete Interval Reference
IntervalSemi-
tones
QualityExample (from C)Song Reference
Unison (P1)0PerfectC → C
Minor 2nd (m2)1MinorC → D♭Jaws theme (dun-dun)
Major 2nd (M2)2MajorC → DHappy Birthday (Hap-py)
Minor 3rd (m3)3MinorC → E♭Greensleeves (A-las)
Major 3rd (M3)4MajorC → EOh When the Saints
Perfect 4th (P4)5PerfectC → FHere Comes the Bride
Tritone (TT)6Augmented/DimC → F♯/G♭The Simpsons (The-Simp)
Perfect 5th (P5)7PerfectC → GStar Wars (main theme)
Minor 6th (m6)8MinorC → A♭The Entertainer
Major 6th (M6)9MajorC → AMy Bonnie Lies Over
Minor 7th (m7)10MinorC → B♭Somewhere (West Side Story)
Major 7th (M7)11MajorC → BTake On Me (chorus)
Octave (P8)12PerfectC → CSomewhere Over the Rainbow

Compound Intervals (Beyond the Octave)

Intervals larger than an octave are called compound intervals. They're the same quality as their simple counterparts, just an octave higher. These show up constantly in chord extensions.

CompoundSemitonesSimple EquivalentChord Usage
Minor 9th13Minor 2nd + octave♭9 chords, altered dominants
Major 9th14Major 2nd + octave9th chords (add9, maj9, dom9)
Minor 10th15Minor 3rd + octaveSpread voicings
Major 10th16Major 3rd + octaveSpread voicings, piano style
Perfect 11th17Perfect 4th + octave11th chords, sus sounds
Sharp 11th18Tritone + octaveLydian chords (#11)
Minor 13th20Minor 6th + octave♭13 chords, altered dom
Major 13th21Major 6th + octave13th chords

Understanding Music Intervals

An interval is the distance between two notes, measured in half steps (semitones). Every melody you hum and every chord you play is built from intervals. Understanding them is the single most useful thing you can learn in music theory.

Interval Qualities

Perfect intervals (unison, 4th, 5th, octave) have a pure, stable sound. They appear in both major and minor scales at the same distance. Major intervals (2nd, 3rd, 6th, 7th) are the distances found in the major scale. Minor intervals are one half step smaller than their major counterparts. The tritone (augmented 4th / diminished 5th) sits exactly in the middle of the octave and creates maximum tension.

Why Intervals Matter for Guitar

Once you can see intervals on the fretboard, chord shapes stop being random finger positions and start making sense. A major chord is always root + major 3rd + perfect 5th, regardless of where you play it. Moving a note by one fret changes the interval by one semitone. This is why guitar is actually one of the most logical instruments for understanding theory — the visual layout maps directly to interval distances.

Ear Training with Intervals

The "song reference" column above gives you a hook for recognizing each interval by ear. The ascending perfect 5th sounds like the Star Wars theme. The ascending perfect 4th sounds like "Here Comes the Bride." With practice, you'll hear intervals everywhere — in melodies, in chord changes, even in car horns and doorbells.

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