GlenCalc

Note frequency calculator

In twelve-tone equal temperament each semitone multiplies the frequency by the twelfth root of 2.

Your answer

Frequency440 Hz
MIDI note number69
Wavelength in air (20 °C)0.78 m

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How we worked it out

Updated as you change the numbers.

  1. f = A4 × 2^((n − 69) ÷ 12), where n is the MIDI note number (A4 = 69).

Method and assumptions

Concert pitch A4 = 440 Hz is the ISO 16 standard. Middle C (C4) is about 261.63 Hz.

Questions

What is the frequency of middle C?

261.63 Hz with A4 = 440 Hz.

Sources

Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.

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