Notes and intervals
Interval
An interval is the distance between two notes, named by a number (third, fifth) and a quality (major, minor, perfect): from C to E is a major third.
What is an interval in music?
An interval measures the distance between two notes. Its name has two parts:
- The number: count the letter names, including both ends. C to E is C, D, E: a third. C to G spans five letters: a fifth.
- The quality: major, minor, perfect, augmented or diminished, depending on the exact number of semitones. C to E is 4 semitones, a major third. C to E♭ is 3, a minor third.
Seconds, thirds, sixths and sevenths are major or minor. Fourths, fifths and octaves are called perfect. Two notes played together form a harmonic interval; one after the other, a melodic interval.
Every interval on the guitar fretboard
Use C at the 3rd fret of the 5th string as the root. Each interval has a fixed spot, and the shape works anywhere as long as you do not cross the B string:
| Interval | Semitones | Note | Where to play it |
|---|---|---|---|
| Minor second | 1 | D♭ | 5th string, 4th fret |
| Major second | 2 | D | 5th string, 5th fret |
| Minor third | 3 | E♭ | 4th string, 1st fret |
| Major third | 4 | E | 4th string, 2nd fret |
| Perfect fourth | 5 | F | 4th string, 3rd fret |
| Tritone | 6 | F# | 4th string, 4th fret |
| Perfect fifth | 7 | G | 4th string, 5th fret |
| Minor sixth | 8 | A♭ | 3rd string, 1st fret |
| Major sixth | 9 | A | 3rd string, 2nd fret |
| Minor seventh | 10 | B♭ | 3rd string, 3rd fret |
| Major seventh | 11 | B | 3rd string, 4th fret |
| Octave | 12 | C | 3rd string, 5th fret |
Move the root to the 5th fret (D) and everything slides up two frets: D, F#, A for a D chord.
Why think in intervals instead of shapes?
A chord is just a formula of intervals. Major: 1, 3, 5. Minor: 1, ♭3, 5. Dominant seventh: 1, 3, 5, ♭7. If you know where the third and the seventh sit around a root, you can build C7, Cm7 or Cmaj7 without memorising three separate grips.
The same goes for soloing: over G7, landing on the third (B) and the seventh (F) instantly sounds inside the chord. In the guitar scales and chords tool, switch the display from note names to intervals to see the same scale from this angle.
Exercise: sing and play the intervals
Play C (5th string, 3rd fret), then each note from the chart, singing both pitches. Start with the most distinct ones: perfect fifth, major third, octave. Then add the tritone, which is easy to spot once you know it.
A few ear anchors: the perfect fourth opens Here Comes the Bride, the perfect fifth opens Twinkle, Twinkle, Little Star, the tritone opens The Simpsons theme. To check an interval you hear inside a chord, enter the notes in the chord identifier.
Key takeaways
- An interval = a number (count the letter names) + a quality (count the semitones).
- Fourths, fifths and octaves are perfect; seconds, thirds, sixths and sevenths are major or minor.
- On the guitar, every interval has a fixed shape from the root.
- Chords and scales are simply lists of intervals.
Frequently asked questions
What is the difference between a major and a minor interval?
A minor interval is one semitone smaller than the major interval with the same number. Major third: 4 semitones (C to E); minor third: 3 (C to E♭). On one string, a single fret is enough to change the colour.
What is an inverted interval?
It is the same pair of notes with the lower one moved up an octave. The numbers always add up to 9: a third becomes a sixth, a fourth becomes a fifth. Major becomes minor and vice versa, perfect stays perfect: C-E (major third) turns into E-C (minor sixth).
Is the tritone an augmented fourth or a diminished fifth?
Both: 6 semitones, the same fret. C to F# is spelled as an augmented fourth, C to G♭ as a diminished fifth. The name depends on the key and on what the note is doing, not on the sound.
Related terms
Practise in the workshop
Take it from theory to the fretboard
Open the workshop tools and see this idea across the whole neck. Free account, no card needed.