interval
C perfect fifth
ClowerGupperP57 half steps
Seven half steps. Stack twelve of them and you land back where you started, give or take a comma.
On the keyboard
What is true of it
C up a perfect fifth is G: 7 half steps, and 5 letters counting both ends.
Turn it upside down — put the C on top — and it becomes a perfect fourth. The two numbers always add to nine, and the two sizes to twelve.
It is a perfect consonance.
Every interval on C
C → D♭minor second · dissonanceC → Dmajor second · dissonanceC → E♭minor third · imperfect consonanceC → Emajor third · imperfect consonanceC → Fperfect fourth · perfect consonanceC → F♯augmented fourth · dissonanceC → G♭diminished fifth · dissonanceC → A♭minor sixth · imperfect consonanceC → Amajor sixth · imperfect consonanceC → B♭minor seventh · dissonanceC → Bmajor seventh · dissonance