C4 (middle C): frequency and where to play it

C4 at every common reference pitch

A note’s frequency depends on what A4 is tuned to. The standard is 440 Hz; the other three are the ones you are most likely to meet. The cents column is how far each one sits from the 440 version — the same for every note, because changing the reference moves the whole scale together.

One cycle of C4 lasts 3.822 ms, and its wavelength in air at 20 °C is 1.31 m. Hold it as a steady tone in the tone generator.

C4 on the piano

C4 is key 40 of 88, counting from the bottom — a white key, the C nearest the middle of the keyboard. Press any key below to compare it with its neighbours.

C4 on the guitar

In standard tuning C4 is played in 4 places: 5th (A) string, fret 15, 4th (D) string, fret 10, 3rd (G) string, fret 5 and 2nd (B) string, fret 1. The same pitch in each place, with a different tone: lower strings sound warmer. Guitar music is written an octave higher than it sounds, so on a guitar part this note is printed as C5.

C4 on the staff

Instruments that can play C4

46 instruments play C4 within the normal range, and 2 reach it only at the extreme of theirs. Each links to its range chart; for a transposing instrument, the note on its part is shown.

Only at the extreme of their range

• Double bass
• Timpani

Voices: C4 is inside the typical range of the bass, baritone, tenor, alto, mezzo-soprano and soprano. Test your own range.

The harmonics of C4

A played C4 is not one frequency. A string or a pipe also sounds whole-number multiples of it, and the mix of those harmonics is the instrument’s tone. Here is where the first eight land — and why the 7th sounds out of tune against a piano.

Frequencies that land on C4

• 256 Hz — the “scientific pitch” middle C

Frequently asked questions

Typing it? C4 is also written C4. Convert any frequency on the Hz-to-note converter.