B7
Reviewed for accuracy · Maintained by Justin Evans
B7 highlighted — use the view toggle to see all 88 keys.
Piano key
87 of 88
Octave
7
Frequency
3951.07 Hz
MIDI number
107
Key color
White key
Pitch class
B · Cb · A##
What is B7?
B7 is the B in octave 7 — the 87th key of the 88 on a full-size piano, counted from the bottom. In standard tuning it sounds at 3951.07 Hz. It sits 47 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 B.
Every octave doubles the frequency: the B one octave up sounds at 7902.14 Hz and the one below at 1975.54 Hz. The same piano key can be written as B, Cb, A## depending on the musical context — same sound, different spelling.
Nearby notes
Every B on the keyboard: