What is 256 Hz?
256 Hz is middle C in “scientific pitch,” a tuning where every C is a power of two; in standard tuning middle C is 261.6 Hz.
In scientific (or philosophical) pitch, C4 is set to exactly 256 Hz = 2⁸, so all Cs fall on neat powers of two (128, 256, 512 Hz…). It is convenient for physics, which is why many older textbooks and tuning forks use it.
Tuning forks at 256 Hz and 512 Hz are still used by doctors for quick hearing and vibration-sense tests. Modern music, however, uses A4 = 440 Hz, which puts middle C at about 261.6 Hz — roughly a third of a semitone higher.
| Nearest note (A4 = 440 Hz) | C4 (261.6 Hz), -38 cents |
|---|---|
| Wavelength in air | 134 cm |
| Period | 3.91 ms per cycle |
| Simulator Chladni mode | (1, 1) |
What the 256 Hz pattern looks like
Harmonic mode layers several overtones on top of the fundamental, a good way to see why a “pure” C still has structure.
The simulator above is already set to 256 Hz. Press Play in the Slider tab to hear the tone, switch pattern modes to compare shapes, and use Record video or Export PNG to keep the result. The address bar always holds a link to exactly what you see, so you can share it.
256 Hz FAQ
Is middle C 256 Hz or 261.6 Hz?
Both are used. 261.6 Hz is middle C in standard A=440 tuning; 256 Hz is middle C in scientific pitch.
Why do tuning forks come in 256 Hz?
Because scientific pitch makes C a power of two, 256 Hz and 512 Hz forks became standard in physics labs and medical hearing tests.