C0 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.
| Reference | C0 | vs 440 |
|---|---|---|
| A4 = 415 Hz · Baroque pitch | 15.42 Hz | −101.3¢ |
| A4 = 432 Hz · “Verdi” pitch | 16.05 Hz | −31.8¢ |
| A4 = 440 Hz · Standard (ISO 16) | 16.35 Hz | — |
| A4 = 442 Hz · Orchestral | 16.43 Hz | +7.9¢ |
One cycle of C0 lasts 61.156 ms, and its wavelength in air at 20 °C is 20.98 m. Hold it as a steady tone in the tone generator.
C0 on the piano
C0 is below the bottom of an 88-key piano, whose lowest key is A0 — 9 semitones lower than that. Press any key below to compare it with its neighbours.
C0 on the guitar
C0 is below the guitar’s lowest note, the open low E (E2), so a guitar in standard tuning cannot play it.
C0 on the staff
Instruments that can play C0
None of the instruments in our range charts reach C0.
C0 is outside the typical range of all six voice types. Test your own range.
The harmonics of C0
A played C0 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.
| Harmonic | Frequency | Nearest note | Off by |
|---|---|---|---|
| 1 (fundamental) | 16.35 Hz | C0 | 0¢ |
| 2 | 32.70 Hz | C1 | 0¢ |
| 3 | 49.05 Hz | G1 | +2.0¢ |
| 4 | 65.41 Hz | C2 | 0¢ |
| 5 | 81.76 Hz | E2 | −13.7¢ |
| 6 | 98.11 Hz | G2 | +2.0¢ |
| 7 | 114.46 Hz | B♭2 | −31.2¢ |
| 8 | 130.81 Hz | C3 | 0¢ |
Frequently asked questions
What is the frequency of C0?
C0 is 16.35 Hz in equal temperament with A4 tuned to 440 Hz, the international standard. At A4 = 432 Hz it is 16.05 Hz, and at the orchestral A4 = 442 Hz it is 16.43 Hz.
Which octave is C0 in?
The number is the octave in scientific pitch notation, where each octave starts on C and C4 is middle C. C0 is in octave 0, 48 semitones below middle C. In Helmholtz notation, used in older books, it is written C₂.
How do I play C0 on a piano?
C0 is below the bottom of an 88-key piano, whose lowest key is A0 — 9 semitones lower than that.
Which instruments can play C0?
None of the instruments we chart reach C0; it is outside the range of ordinary instruments.
Typing it? C0 is also written C0. Convert any frequency on the Hz-to-note converter.