Musical Note Frequency Calculator

About this calculator

This calculator finds the frequency in hertz of a musical note under 12-tone equal temperament: f = A4 × 2^((n−69)/12), where n is the note's MIDI number and A4 is the reference tuning pitch (usually 440 Hz, though orchestras sometimes tune to 442 Hz or other values). Each semitone step multiplies or divides the frequency by the twelfth root of two.

Musicians, piano tuners, instrument builders, and audio/synth developers use it to look up the exact pitch of any note and octave, verify a tuner's readings, or generate reference tones for software synthesizers. Enter the note name and octave, and optionally change the A4 reference, to get the precise frequency.