C3
130.813Hz at concert pitch
Press to hear a pure sine tone at this pitch.
MIDI note
48
Piano key
28
Octave
3
Frequency
130.813 Hz
Period
7.6445 ms
Wavelength
2.6221 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 48 is C3. Yamaha gear labels the same key C2 and some trackers call it C4. The MIDI number never moves — only the octave name printed on the box does.
At other reference pitches
| Reference (A4) | C3 frequency | Where you meet it |
|---|---|---|
| 432 Hz | 128.434 Hz | the alternative-tuning circle |
| 440 Hzstandard | 130.813 Hz | the ISO 16 standard — concert pitch |
| 442 Hz | 131.407 Hz | many European orchestras tune a touch sharp |
| 443 Hz | 131.705 Hz | some sharper continental orchestras |
Every row is C3 — only the A4 you tune to changes. A frequency scales straight with the reference: C3 at 432 Hz is the 440 Hz value times 432⁄440.
Move around
Every C
Chords with C in them
C appears in each of these — see the whole chord grid.