Interval reference
Major third
3 letter names · 4 semitones · C → E
A major third spans 3 letter names and 4 semitones. Both halves of that description matter: the number comes from the letters, the quality from the exact size.
Starting on C, a major third reaches E. Its shorthand is M3, and traditionally it counts as imperfect consonance.
How big it is
Turned upside down
Move the lower note up an octave and a major third becomes a minor sixth. The two numbers add up to nine, and the quality flips — major with minor, augmented with diminished, while perfect stays perfect.
Where you meet it
- The lower third of a major triad
- The upper third of a minor triad
From every starting note
| From | Up a major third |
|---|---|
| C | E |
| C♯ | E♯ |
| D | F♯ |
| D♯ | F𝄪 |
| E | G♯ |
| F | A |
| F♯ | A♯ |
| G | B |
| G♯ | B♯ |
| A | C♯ |
| A♯ | C𝄪 |
| B | D♯ |