interval
G perfect fifth
GlowerDupperP57 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
G up a perfect fifth is D: 7 half steps, and 5 letters counting both ends.
Turn it upside down — put the G 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 G
G → A♭minor second · dissonanceG → Amajor second · dissonanceG → B♭minor third · imperfect consonanceG → Bmajor third · imperfect consonanceG → Cperfect fourth · perfect consonanceG → C♯augmented fourth · dissonanceG → D♭diminished fifth · dissonanceG → E♭minor sixth · imperfect consonanceG → Emajor sixth · imperfect consonanceG → Fminor seventh · dissonanceG → F♯major seventh · dissonance