C4 on the staff and the piano
On the treble clef, C4 sits on the first ledger line below the staff. On a grand staff, middle C sits on its own short ledger line between the treble and bass staves, so it can be written in either clef.
On the piano, C4 is key 40 of 88, octave 4 - a white key. It is middle C, key 40, near the centre of the keyboard.
Play it on the online piano, or see all 88 note frequencies on one page.
C4 at a glance
All values assume twelve-tone equal temperament at the international standard pitch of A4 = 440 Hz. In that system every semitone has the same size - a frequency ratio of 2^(1/12) - so C4 is exactly 440 × 2^(-9/12) Hz. Under alternative references the note shifts with the reference: at A4 = 432 Hz, C4 becomes 256.87 Hz.
C in every octave
| Note | Frequency | MIDI | Piano key |
|---|---|---|---|
| C1 | 32.70 Hz | 24 | 4 |
| C2 | 65.41 Hz | 36 | 16 |
| C3 | 130.81 Hz | 48 | 28 |
| C4 ← | 261.63 Hz | 60 | 40 |
| C5 | 523.25 Hz | 72 | 52 |
| C6 | 1046.5 Hz | 84 | 64 |
| C7 | 2093.0 Hz | 96 | 76 |
| C8 | 4186.0 Hz | 108 | 88 |
Each octave doubles the frequency - the simplest relationship in music, and the reason notes an octave apart sound like “the same note, higher”.
Who plays C4
C4 is within the usual range of the piano, guitar, bass guitar, violin, viola, cello, double bass, flute, clarinet, trumpet and trombone. Among voice types it falls in the usual range of soprano, mezzo-soprano, alto, tenor, baritone and bass.
- Piano: A0–C8
- Guitar (standard tuning): E2–E6
- Bass guitar (4-string): E1–G4
- Violin: G3–A7
- Viola: C3–E6
- Cello: C2–A5
- Double bass: E1–G4
- Flute: C4–C7
- Clarinet (B♭): D3–B♭6
- Trumpet (B♭): E3–B♭5
- Trombone (tenor): E2–F5
- Soprano: C4–C6
- Mezzo-soprano: A3–A5
- Alto (contralto): F3–F5
- Tenor: C3–C5
- Baritone: A2–A4
- Bass voice: E2–E4
Ranges are approximate: they are the commonly cited sounding (concert) pitches, and real ranges vary by player, instrument, tuning and repertoire. Guitar, bass guitar and double bass are written an octave higher than they sound; B♭ clarinet and trumpet are written a whole tone higher.
Neighboring notes
One semitone down is B3 at 246.94 Hz; one semitone up is C♯4 at 277.18 Hz. Need a frequency between notes, or a different waveform? The tone generator plays anything from 20 Hz to 20 kHz; the note ↔ frequency converter does the math both directions, and the chromatic tuner listens to your instrument and shows the offset in cents.