C#3 — 138.59 Hz
C#3 (MIDI 49) vibrates 138.59 times per second at standard concert pitch. Play the reference tone below, or tune to it with the online tuner.
C#3 at different reference pitches
| Reference (A4) | C#3 frequency | Used for |
|---|---|---|
| 415 Hz | 130.72 Hz | Baroque pitch |
| 432 Hz | 136.07 Hz | “Verdi” pitch |
| 440 Hz | 138.59 Hz | Standard concert pitch |
| 442 Hz | 139.22 Hz | European orchestras |
| 444 Hz | 139.85 Hz | European orchestras |
Physical properties
- Period: one cycle every 7.22 ms
- Wavelength in air: ≈ 2.47 m (at 20 °C, 343 m/s)
- MIDI note number: 49
- Octave up: C#4 = 277.18 Hz · Octave down: 69.30 Hz