Guitar Intervals Explained

Intervals are the atoms of music theory. Every scale formula, chord recipe, and melodic phrase is built from intervals. Once you understand their names, sounds, and positions on the fretboard, scales, chords, and improvisation start to make sense.

Try it interactively

The Scale Explorer highlights notes with interval labels (R, b3, 5, b7…). See it in action.

See Intervals on Fretboard

What Is an Interval?

An interval measures the distance between two notes. On guitar, every fret = 1 semitone. So the interval between fret 5 and fret 7 on the same string is 2 semitones, which is a major 2nd (whole step).

Intervals have two properties: quantity (the number: 2nd, 3rd, 4th…) and quality(perfect, major, minor, diminished, augmented). Together these fully describe the distance.

The 12 Intervals

Semitones	Symbol	Name	Sound Quality	Guitar Example
0	R/1	Unison	Same pitch	Any open string to itself
1	b2	Minor 2nd	Tense, dissonant	E→F (frets 0–1, string 1)
2	2	Major 2nd	Stepwise motion	Open A → B (frets 0–2)
3	b3	Minor 3rd	Dark, minor feel	E→G (frets 0–3)
4	3	Major 3rd	Bright, major feel	G→B (open G–B strings)
5	4	Perfect 4th	Stable, open	E→A (strings 6–5 open)
6	b5	Tritone / Dim. 5th	Maximum tension	B→F (open str 2 → fret 1 str 1)
7	5	Perfect 5th	Strong, powerful	A→E (open strings 5–1)
8	b6	Minor 6th	Wistful, minor	E→C (frets 0–8)
9	6	Major 6th	Warm, jazzy	G→E (frets 0–9)
10	b7	Minor 7th	Bluesy, dominant	G→F (frets 0–10)
11	7	Major 7th	Dreamy, tense	C→B (frets 0–11)
12	8	Octave	Same note, higher	Any note + 12 frets

Interval Quality

Perfect Intervals

The unison, 4th, 5th, and octave are called "perfect" because they are maximally consonant and do not have major/minor variants. The perfect 5th (7 semitones) is the most powerful interval on guitar. It's the basis of power chords and the harmonic series.

RUnison

4Perf. 4th

5Perf. 5th

8Octave

Major and Minor Intervals

Seconds, thirds, sixths, and sevenths come in major and minor versions. Lower a major interval by one semitone and it becomes minor. The 3rd is the most important of these: major 3rd = bright chord, minor 3rd = dark chord.

The Tritone

The tritone (6 semitones) is unique: it divides the octave exactly in half. It is the most dissonant interval in tonal music and was historically called diabolus in musica (the devil in music). On guitar it is the "blue note" in the blues scale and the defining tension of a dominant 7th chord (the 3rd and 7th of G7 form a tritone: B–F).

Finding Intervals on the Fretboard

On a single string, counting frets directly gives you intervals. Across strings, certain patterns become useful shortcuts:

Interval	Same String	Across Adjacent Strings (E–A, A–D, D–G, B–e)
Octave (12)	+12 frets	+2 frets, skip one string
Perfect 5th (7)	+7 frets	+2 frets, next string
Perfect 4th (5)	+5 frets	Same fret, next string
Major 3rd (4)	+4 frets	–1 fret, next string (G–B: same fret)
Minor 3rd (3)	+3 frets	–2 frets, next string (G–B: –1 fret)

Hearing Intervals

Ear training (recognising intervals by sound) is one of the most valuable skills you can develop as a musician. The classic method is to associate each interval with a familiar song opening:

Minor 2nd (b2): Jaws theme
Major 2nd (2): Happy Birthday (first two notes)
Minor 3rd (b3): Smoke on the Water (main riff)
Major 3rd (3): When the Saints Go Marching In
Perfect 4th (4): Here Comes the Bride
Tritone (b5): The Simpsons theme
Perfect 5th (5): Star Wars theme
Major 6th (6): My Bonnie Lies Over the Ocean
Minor 7th (b7): Somewhere (West Side Story)
Major 7th (7): Take On Me (A-ha)
Octave (8): Somewhere Over the Rainbow

Intervals and Chord Theory

Every chord is a stack of intervals above a root note. Knowing intervals means you can build and name any chord from scratch:

Chord	Intervals from Root
Major triad	Root + Major 3rd (4) + Perfect 5th (7)
Minor triad	Root + Minor 3rd (3) + Perfect 5th (7)
Dom. 7th	Root + M3 + P5 + Minor 7th (10)
Major 7th	Root + M3 + P5 + Major 7th (11)
Minor 7th	Root + m3 + P5 + Minor 7th (10)
Power chord	Root + Perfect 5th (7)

Frequently Asked Questions

What is a musical interval?

A musical interval is the distance in pitch between two notes, measured in semitones (half steps). Intervals give chords and scales their characteristic sound. The major 3rd makes a chord sound bright, the minor 3rd makes it darker, and the tritone creates maximum tension.

What is the difference between a semitone and a whole tone?

A semitone (half step) is the smallest interval in Western music. Adjacent frets on a guitar are one semitone apart. A whole tone (whole step) is two semitones, skipping one fret. The major scale is built from a pattern of whole and half steps: W W H W W W H.

What is a perfect interval?

The perfect intervals (unison, perfect 4th, perfect 5th, and octave) have a particularly stable, consonant sound. They are called 'perfect' because they appear in nearly every musical culture and do not have major/minor variants, unlike 3rds or 6ths.

What is a tritone?

The tritone is the interval of 6 semitones, exactly halfway between the octave. Also called the diminished 5th (b5) or augmented 4th (#4), it is the most dissonant interval in Western music. It's the 'blue note' in the blues scale and the interval that gives dominant 7th chords their tension.

How do intervals relate to scales and chords?

Scales are sequences of intervals. Chords are stacks of intervals (root + 3rd + 5th for a triad). Every scale formula and chord formula is written as a list of intervals from the root. Understanding intervals lets you build any scale or chord from any root note without memorising each one separately.