F9
11,175.303Hz at concert pitch
Press to hear a pure sine tone at this pitch.
MIDI note
125
Piano key
—
Octave
9
Frequency
11,175.303 Hz
Period
0.0895 ms
Wavelength
0.0307 m
Pitch class
F
Notation
SPN
MIDI is the note number synths and software pass around (0–127). Pitch class is the note without its octave — all the Fs share one. This note falls outside the 88-key piano, so it has no piano key number.
At other reference pitches
| Reference (A4) | F9 frequency | Where you meet it |
|---|---|---|
| 432 Hz | 10,972.116 Hz | the alternative-tuning circle |
| 440 Hzstandard | 11,175.303 Hz | the ISO 16 standard — concert pitch |
| 442 Hz | 11,226.1 Hz | many European orchestras tune a touch sharp |
| 443 Hz | 11,251.499 Hz | some sharper continental orchestras |
Every row is F9 — only the A4 you tune to changes. A frequency scales straight with the reference: F9 at 432 Hz is the 440 Hz value times 432⁄440.
Move around
Every F
Chords with F in them
F appears in each of these — see the whole chord grid.