MIDI Note Frequency Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 27, 2026The math tuning every digital instrument
MIDI assigns each of 128 possible notes a number, with the frequency for any note calculated relative to a single reference point: MIDI note 69, defined as exactly 440 Hz, the standard international concert pitch for the note A4.
Worked example
For MIDI note 69 (the reference note itself):
f = 440 x 2^((69-69)/12) = 440.0 Hz
This confirms the formula returns exactly 440 Hz for note 69, as it must by definition - every other MIDI note's frequency is calculated as a power of the twelfth root of 2 away from this anchor point, the mathematical foundation of the 12-tone equal temperament tuning system used throughout modern Western music.