Chapter 6 | Intervals Between the Scale Notes
The major scale gives us a reference. Now we can describe the notes around it.
C major contains C, D, E, F, G, A and B. But music also uses the notes between them. We can name those distances by adjusting the major-scale intervals you already know.
Lower a major interval
Lower the upper note of a major second, third, sixth or seventh by one semitone and the interval becomes minor.
C–E is a major third. Lower E to E♭ and C–E♭ becomes a minor third. On the guitar, that means moving the upper note down one fret while keeping the starting note in place.
| Major interval | Lower the upper note | Result |
|---|---|---|
| C–D | D becomes D♭ | Minor second |
| C–E | E becomes E♭ | Minor third |
| C–A | A becomes A♭ | Minor sixth |
| C–B | B becomes B♭ | Minor seventh |
Change a perfect interval
Lower the upper note of a perfect fourth or fifth by one semitone and the interval becomes diminished. Raise it by one semitone and it becomes augmented.
Start with C–G, a perfect fifth:
- C–G♭: diminished fifth, written ♭5 in chord and scale formulas.
- C–G: perfect fifth, written 5.
- C–G♯: augmented fifth, written ♯5.
Major → one semitone smaller → minor.
Perfect → one semitone smaller → diminished.
Major or perfect → one semitone larger → augmented.
These rules apply while the interval’s letter-name span stays the same. Lowering a minor interval another semitone makes it diminished. For now, we’ll concentrate on the common examples above.
Same fret, different name
Pitch and spelling tell us different parts of the story.
On a normally tuned guitar, F♯ and G♭ land on the same fret. From C, however, they have different interval names:
- C–F♯ is an augmented fourth. Count the letters: C, D, E, F.
- C–G♭ is a diminished fifth. Count the letters: C, D, E, F, G.
Both cover six semitones. The letter names explain why one is a fourth and the other is a fifth.
| Spelling | Letter span | Interval | Semitones |
|---|---|---|---|
| C–F♯ | C D E F | Augmented fourth | 6 |
| C–G♭ | C D E F G | Diminished fifth | 6 |
| C–D♯ | C D | Augmented second | 3 |
| C–E♭ | C D E | Minor third | 3 |
The six-semitone interval is often called a tritone. That name describes its size. “Augmented fourth” and “diminished fifth” also tell us how the notes are spelled.
Count letters for the number. Count semitones for the quality. Both matter.
E♯ is a real note name
E♯ sounds like F on the guitar. C♭ sounds like B. B♯ sounds like C, and F♭ sounds like E. These are useful spellings, rather than extra pitches hiding between the frets.
For example, the fifth of A is E. Raise that fifth by one semitone and write E♯, so the letters still show a fifth: A–B–C–D–E. Writing F would describe a different letter span.
A map of the octave
Use C as a clear example, then move the same distances to another root.
| Note above C | Formula | Interval name | Semitones |
|---|---|---|---|
| C | 1 | Perfect unison | 0 |
| D♭ | ♭2 | Minor second | 1 |
| D | 2 | Major second | 2 |
| E♭ | ♭3 | Minor third | 3 |
| E | 3 | Major third | 4 |
| F | 4 | Perfect fourth | 5 |
| F♯ / G♭ | ♯4 / ♭5 | Augmented fourth / diminished fifth | 6 |
| G | 5 | Perfect fifth | 7 |
| A♭ | ♭6 | Minor sixth | 8 |
| A | 6 | Major sixth | 9 |
| B♭ | ♭7 | Minor seventh | 10 |
| B | 7 | Major seventh | 11 |
| C (higher) | 8 | Perfect octave | 12 |
These formulas measure from a chosen root. A ♭3 means a minor third above that root; it does not mean “the third note in every scale.”
Hear the interval change
Major third to minor third
On the A string, play C at fret 3 followed by E at fret 7. Then play C followed by E♭ at fret 6.
Repeat slowly. The starting note stays in place. The upper note moves down one fret. This is the major-to-minor change from Chapter 4, heard as an interval.
Perfect fifth to diminished fifth
Now compare C–G at frets 3 and 10 with C–G♭ at frets 3 and 9 on the A string.
| Interval | Notes | A-string frets |
|---|---|---|
| Major third | C → E | 3 → 7 |
| Minor third | C → E♭ | 3 → 6 |
| Perfect fifth | C → G | 3 → 10 |
| Diminished fifth | C → G♭ | 3 → 9 |
Numbers above the octave
An interval larger than an octave is a compound interval. To name a simple interval extended by one octave, add seven to its number:
- A second plus an octave is a ninth.
- A fourth plus an octave is an eleventh.
- A sixth plus an octave is a thirteenth.
The quality stays the same. A major second extended by an octave becomes a major ninth.
Check your understanding
Write your answers before opening the answer section.
1. Find the notes above E
Work from the E major scale, then adjust the note named by the number:
E · F♯ · G♯ · A · B · C♯ · D♯
Find the note for each interval above E:
- ♭2
- ♭3
- ♯4
- ♭5
- ♯5
- ♭6
- ♭7
2. Name the intervals
Give the full interval names for C–D♭, C–E♭, C–G♭ and C–G♯. Assume each upper note is above C within the same octave.
3. Explain the spelling
F♯ and G♭ sound alike on the guitar. Why do C–F♯ and C–G♭ have different interval names?
4. Raise the fifth
The fifth of D is A. What note name describes D’s raised fifth?
5. Think about E♯
Does the spelling E♯ describe an extra pitch between E and F? Explain.
6. Go beyond the octave
What do we call a second plus an octave?
Check your answers
1. Intervals above E
- ♭2 = F: minor second.
- ♭3 = G: minor third.
- ♯4 = A♯: augmented fourth.
- ♭5 = B♭: diminished fifth.
- ♯5 = B♯: augmented fifth.
- ♭6 = C: minor sixth.
- ♭7 = D: minor seventh.
2. Interval names
- C–D♭: minor second.
- C–E♭: minor third.
- C–G♭: diminished fifth.
- C–G♯: augmented fifth.
3. Different letters, different spans
C to F is a fourth; C to G is a fifth. The accidental changes the quality, not the letter span. Both examples cover six semitones.
4. D’s raised fifth
A♯. It keeps the fifth’s letter, A, while raising its pitch by one semitone.
5. E♯
No. E♯ shares the pitch and fret of F on the guitar. Its spelling shows its role in the music.
6. A second plus an octave
A ninth. For example, C to the D above the next C is a major ninth.
What to remember
A fret tells you the pitch. An interval name tells you how that pitch relates to another note.
The letter names give the interval its number. The distance in semitones determines its quality. Together, they explain both the sound and the spelling.
Next: hear how notes and chords gather around a tonal centre.