Note frequency chart

How the numbers work

Every note is the one before it times the twelfth root of two (about 1.0595), so each octave doubles the frequency: A3 is 220 Hz, A4 is 440 Hz, A5 is 880 Hz. The formula is f = 440 × 2^{(n − 69) / 12}, where n is the MIDI number. The wavelength is the speed of sound (343 m/s, in air at 20 °C) divided by the frequency.

Phone speakers can't really play the lowest octaves: below about 100 Hz you mostly hear the overtones, so the tone here adds a little of them. Headphones get closer. C0 at 16.35 Hz sits at the bottom edge of human hearing anyway.

440 or 432?

A4 = 440 Hz has been the standard pitch since 1939 (ISO 16); almost every tuner, piano and recording uses it. Some people prefer A4 = 432 Hz, about a third of a semitone lower. It isn't proven to be healthier or more natural, but it's a real choice, and the switch above recalculates every note for it. To tune to it, use the 432 Hz tuner; for anything else, the tuners; to hold one frequency for a while, the tone generator.

Then make something of it

The note you tapped last goes into Brumm as a melody, inside a club track with a beat and a bass. No account, no upload: the note travels inside the link itself. Hum a whole line there, and it becomes an instrument.

Nothing leaves your phone: the tones are made in the browser. How the site counts visits.