Piano note
C4 Piano Note Frequency
C4 is key 40 of the 88 on a standard piano, with a frequency of 261.63 Hz when the piano is tuned to A4 = 440 Hz.
261.63 Hz
C4 at a glance
- Frequency (A4 = 440 Hz)
- 261.63 Hz
- At A4 = 442 Hz
- 262.81 Hz
- At A4 = 432 Hz
- 256.87 Hz
- Piano key number
- 40 / 88
- MIDI note number
- 60
- Octave
- 4
- Key colour
- White key
- Wavelength in air
- 1.31 m
- Period (one vibration)
- 3.82 ms
- Register
- Middle
Wavelength assumes sound travels at 343 m/s (air at about 20 °C).
About this part of the keyboard
C4 is middle C, the C closest to the middle of the keyboard and a common reference point for reading music.
This is the heart of the keyboard around middle C. On most pianos each note here has three plain steel strings (a trichord) that must match each other exactly. Tuners usually start here, setting the temperament octave and A4 before tuning the rest of the piano from it.
Neighbouring keys
Is your C4 in tune?
Play C4 on your piano and our free online tuner will show how many cents it is from 261.63 Hz.
Open the piano tunerPiano sounding off?
If your piano is more than a few cents off, it's time for a tuning. We tune pianos across Israel.
Book a Tuning