G♯4 / A♭4
G♯4 highlighted — use the view toggle to see all 88 keys.
Piano key
48 of 88
Octave
4
Frequency
415.3 Hz
MIDI number
68
Key color
Black key
Pitch class
G#, Ab
What is G♯4?
G♯4 is the G♯ in octave 4 — the 48th key of the 88 on a full-size piano, counted from the bottom. In standard tuning it sounds at 415.3 Hz. It sits 8 half-steps above middle C (C4).
To find it, locate any group of two black keys: the white key just to their left is a C. Count up from middle C (C4) within the same octave to reach octave 4, then step to G♯.
Every octave doubles the frequency: the G♯ one octave up sounds at 830.6 Hz and the one below at 207.65 Hz. The same piano key can be written as G#, Ab depending on the musical context — same sound, different spelling.
Nearby notes
Every G♯ on the keyboard: