Perfect fifth interval
The perfect fifth interval consists of two notes with a distance of seven semitones. For example, C to G note will result in this musical interval.
The name “perfect” dates back to the Medieval when certain intervals – the unison, fourth, fifth and octave – were considered most consonant and were given the name perfect; it constitutes a tonal middle point relationship, which is schematic illustrated in the circle of fifths. The perfect fifth interval is abbreviated P5 (an alternate spelling is diminished sixth).
A perfect fifth C to G on the keyboard.
Listen to the perfect fifth interval (C-G):
This interval is the same that constitutes the 5th chord. For example, C5 with the notes C and G or D5 with the notes D and F#.
To distinguish this interval by ear, it helps to think of familiar songs which first notes match it. One such example is the children song "Twinkle, Twinkle, Little Star", that starts with an ascending P5 (in C Major: C-G).
A perfect twelfth is an octave plus a perfect fifth (or compound perfect fifth, which is the correct term), which in total spans 19 semitones.
Ascending perfect fifth intervals
A list of ascending perfect fifth intervals:
- C – G
- C#/Db – G#/Ab
- D – A
- D#/Eb – A#/Bb
- E – B
- F – C
- F#/Gb – C#/Db
- G – D
- G#/Ab – D#/Eb
- A – E
- A#/Bb – F
- B – F#
Inversions of these intervals will result in perfect fourth intervals.
Below is an example with ascending fifth intervals in pairs:
Descending perfect fifth intervals
A list of descending perfect fifth intervals:
- C#/Db – F#/Gb
- D – G
- D#/Eb – G#/Ab
- E – A
- F – A#/Bb
- F#/Gb – B
- G – C
- G#/Ab – C#/Db
- A – D
- A#/Bb – D#/Eb
- B – E
- C – F
Below is an example with descending fifth intervals in pairs:
See also the Circle of fifths.
Diminished fifth (tritone)
A related interval is the diminished fifth, or tritone (abbreviated TT), sometimes referred to the "devil's interval" due to its dissonant sound.
It includes one semitone less than the perfect fifth interval and makes up a half octave. For example, C to Gb. Because of the half octave distance, an inversion of a tritone will always be another tritone.
The sound of the diminished fifth is dissonant and the interval is used in few chords, but can be found in diminished chords. For example, Cdim which includes the notes C, Eb, Gb and Cdim7 which includes C, Eb, Gb, A.
Listen to the tritone interval (C-Gb):
A diminished fifth C to Gb on the keyboard.
Note that the diminished fifth is identical with the augmented fourth.
Read more about intervals and use the interactive Piano Interval Finder tool.