A7
Reviewed for accuracy · Maintained by Justin Evans
A7 highlighted — use the view toggle to see all 88 keys.
Piano key
85 of 88
Octave
7
Frequency
3520 Hz
MIDI number
105
Key color
White key
Pitch class
A · G## · Bbb
What is A7?
A7 is the A in octave 7 — the 85th key of the 88 on a full-size piano, counted from the bottom. In standard tuning it sounds at 3520 Hz. It sits 45 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 7040 Hz and the one below at 1760 Hz. The same piano key can be written as A, G##, Bbb depending on the musical context — same sound, different spelling.
Nearby notes
Every A on the keyboard: