A♯7 / B♭7
Reviewed for accuracy · Maintained by Justin Evans
A♯7 highlighted — use the view toggle to see all 88 keys.
Piano key
86 of 88
Octave
7
Frequency
3729.31 Hz
MIDI number
106
Key color
Black key
Pitch class
A# · Bb · Cbb
What is A♯7?
A♯7 is the A♯ in octave 7 — the 86th key of the 88 on a full-size piano, counted from the bottom. In standard tuning it sounds at 3729.31 Hz. It sits 46 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) 3 octaves to reach octave 7, then step to A♯.
Every octave doubles the frequency: the A♯ one octave up sounds at 7458.62 Hz and the one below at 1864.66 Hz. The same piano key can be written as A#, Bb, Cbb depending on the musical context — same sound, different spelling.
Nearby notes
Every A♯ on the keyboard: