C8
4,186.009Hz at concert pitch
Press to hear a pure sine tone at this pitch.
MIDI note
108
Piano key
88
Octave
8
Frequency
4,186.009 Hz
Period
0.2389 ms
Wavelength
0.0819 m
Pitch class
C
Notation
SPN
MIDI is the note number synths and software pass around (0–127). Pitch class is the note without its octave — all the Cs share one.
The octave-numbering trap: this site uses scientific pitch notation, where MIDI 108 is C8. Yamaha gear labels the same key C7 and some trackers call it C9. The MIDI number never moves — only the octave name printed on the box does.
At other reference pitches
| Reference (A4) | C8 frequency | Where you meet it |
|---|---|---|
| 432 Hz | 4,109.9 Hz | the alternative-tuning circle |
| 440 Hzstandard | 4,186.009 Hz | the ISO 16 standard — concert pitch |
| 442 Hz | 4,205.036 Hz | many European orchestras tune a touch sharp |
| 443 Hz | 4,214.55 Hz | some sharper continental orchestras |
Every row is C8 — only the A4 you tune to changes. A frequency scales straight with the reference: C8 at 432 Hz is the 440 Hz value times 432⁄440.
About this note
The highest note on a standard 88-key piano — piano key 88, the last key on the right. Its fundamental sits above 4 kHz, up where the piano's tone is more sparkle than melody.
Move around
Every C
Chords with C in them
C appears in each of these — see the whole chord grid.