Interval reference
Perfect fifth
5 letter names · 7 semitones · C → G
A perfect fifth spans 5 letter names and 7 semitones. Both halves of that description matter: the number comes from the letters, the quality from the exact size.
Starting on C, a perfect fifth reaches G. Its shorthand is P5, and traditionally it counts as perfect consonance.
How big it is
Hear it from any note
The explorer starts on C up to G. Play it one note after the other and then both together — the two ways a perfect fifth turns up in music — then change the bottom note: the distance stays the same while the spelling follows the letters.
Turned upside down
Move the lower note up an octave and a perfect fifth becomes a perfect fourth. 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 root to the fifth of every major and minor triad (C up to G in C major)
- Neighbouring open strings on a violin (G up to D)
From every starting note
| From | Up a perfect fifth |
|---|---|
| C | G |
| C♯ | G♯ |
| D | A |
| D♯ | A♯ |
| E | B |
| F | C |
| F♯ | C♯ |
| G | D |
| G♯ | D♯ |
| A | E |
| A♯ | E♯ |
| B | F♯ |