C♯2 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 | C♯2 | vs 440 |
|---|---|---|
| A4 = 415 Hz · Baroque pitch | 65.36 Hz | −101.3¢ |
| A4 = 432 Hz · “Verdi” pitch | 68.04 Hz | −31.8¢ |
| A4 = 440 Hz · Standard (ISO 16) | 69.30 Hz | — |
| A4 = 442 Hz · Orchestral | 69.61 Hz | +7.9¢ |
One cycle of C♯2 lasts 14.431 ms, and its wavelength in air at 20 °C is 4.95 m. Hold it as a steady tone in the tone generator.
C♯2 on the piano
C♯2 is key 17 of 88, counting from the bottom — the black key between C and D. Press any key below to compare it with its neighbours.
C♯2 on the guitar
C♯2 is below the guitar’s lowest note, the open low E (E2), so a guitar in standard tuning cannot play it.
C♯2 on the staff
Instruments that can play C♯2
16 instruments play C♯2 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.
Bowed strings
Guitars and basses
Plucked and struck strings
Tuned percussion
Keyboards and free reeds
Only at the extreme of their range
C♯2 is outside the typical range of all six voice types. Test your own range.
The harmonics of C♯2
A played C♯2 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) | 69.30 Hz | C♯2 | 0¢ |
| 2 | 138.59 Hz | C♯3 | 0¢ |
| 3 | 207.89 Hz | A♭3 | +2.0¢ |
| 4 | 277.18 Hz | C♯4 | 0¢ |
| 5 | 346.48 Hz | F4 | −13.7¢ |
| 6 | 415.77 Hz | A♭4 | +2.0¢ |
| 7 | 485.07 Hz | B4 | −31.2¢ |
| 8 | 554.37 Hz | C♯5 | 0¢ |
Frequently asked questions
What is the frequency of C♯2?
C♯2 is 69.30 Hz in equal temperament with A4 tuned to 440 Hz, the international standard. At A4 = 432 Hz it is 68.04 Hz, and at the orchestral A4 = 442 Hz it is 69.61 Hz.
Is C♯2 the same note as D♭2?
On a piano, a guitar or a tuner, yes: C♯2 and D♭2 are the same key and the same frequency, 69.30 Hz, in equal temperament. They are two names for one pitch (enharmonic equivalents). Which one is written depends on the key — sharps in sharp keys, flats in flat keys — and a string or wind player may pitch them a few cents apart when playing in just intonation.
How do I play C♯2 on a piano?
C♯2 is key 17 of 88, counting from the bottom — the black key between C and D.
Which instruments can play C♯2?
16 of the instruments we chart play C♯2 within their normal range, including cello, double bass, 7-string guitar, 8-string guitar, brazilian 7-string guitar, and 2 more reach it only at the extreme of their range.
Typing it? C♯2 is also written C#2 or Db2. Convert any frequency on the Hz-to-note converter.