Musical pitch

Published June 29, 2026 · By NumberWiki

Category Concepts

Every musical note is really a number — a frequency, measured in hertz (cycles per second). The A above middle C vibrates at 440 times a second; play a note an octave higher and the frequency exactly doubles. That tidy relationship between numbers and sound is why a plain integer can also be heard as a pitch.

Three ways to tune

To turn frequencies into named notes you first have to fix one reference pitch; everything else follows from equal temperament (each semitone multiplies the frequency by the twelfth root of two, ≈ 1.0595). NumberWiki names notes against three references:

• Concert pitch — A4 = 440 Hz, the modern international standard (ISO 16). Most music you hear is tuned to this.
• Scientific pitch — C4 = 256 Hz, on which every C is an exact power of two (C4 = 2⁸). Neat for arithmetic, rare in practice; it puts A4 at about 430.5 Hz.
• Baroque pitch — A4 = 415 Hz, roughly a semitone below concert, the de-facto standard for historically-informed performance of early music.

The popular 432 Hz "Verdi" tuning sits between these and is, in practice, almost indistinguishable from scientific pitch. Tunings only really change which note a frequency is closest to when they differ by a good fraction of a semitone — which is why Baroque, a whole semitone down, is the one that genuinely shifts the names.

Play a note

Pick a tuning, then click the keys. Each key sounds its note in the selected reference.

The notes, C3 to C5

The same two octaves as a table — each frequency links to that number's page, so you can jump from a pitch straight to everything else we know about the rounded integer.

See also

• Any number page shows its frequency reading and "Play" buttons — try 440 (concert A), 256 (scientific middle C), 60 (mains hum, ≈ B♭1), or 8000 (a high, bright tone).
• Small integers are also MIDI note numbers: 60 is middle C, 69 is concert A.
• 432 Hz — the alternative-tuning frequency, and why it's nearly the same as scientific pitch.