Note frequency chart

With A4 tuned to 440 Hz, middle C (C4) is 261.63 Hz. Each octave up doubles the frequency, and each of the twelve semitones in it multiplies the frequency by the twelfth root of 2, about 1.0595. The chart has every note from C1 to B7, and every frequency on it plays when you press it.

Every note, in hertz

Press a frequency to hear it. Press a note's name for its own page. On a phone, the chart scrolls sideways to the higher octaves.

The formula

In equal temperament, which is how pianos and almost all modern instruments are tuned, a note n semitones above A4 has the frequency 440 × 2^n/12 Hz. A note below A4 has a negative n. So A5 is 880 Hz, A3 is 220 Hz, and E5, seven semitones above A4, is 659.26 Hz.

Why 440

A4 = 440 Hz is the standard concert pitch, set as ISO 16. Before standards, tuning varied from town to town and decade to decade. Today some orchestras tune slightly higher, and groups playing older music on period instruments often tune to 415 Hz, close to a semitone lower. Solfeto plays every tone at A4 = 440 Hz.

The range Solfeto plays

Solfeto's training tones run from C2 to B5, 65.41 to 987.77 Hz, the middle of a piano where most music lives. Each tone is a pitch class in a random one of those octaves, because the note is the answer, and a C is a C at 65.41 Hz and at523.25 Hz alike.

A frequency is not a pitch class, though. Someone with absolute pitch hears "C", not "261.63". This chart is for reference, and for hearing how the same note sounds across octaves. How the names work is in the names of the notes.