What Is a MIDI Note to Frequency Calculator?
Every MIDI note is a number from 0 to 127 rather than a pitch — it's up to the synthesizer to translate that number into an actual sound frequency. This calculator does that translation for you, converting any MIDI note number into its frequency in Hz, its musical note name and octave, its period, and its wavelength in air.
This is the exact math used inside every MIDI-compatible synthesizer, DAW and sample library to turn a note-on message into an audible pitch under standard 12-tone equal temperament.
How to Read Your Results
Frequency
The pitch of the note in Hertz (cycles per second). This is the number you'd plug into an oscillator, synth patch, or tuner to reproduce the exact pitch.
Note Name
The standard musical name and octave for the MIDI number, using the scientific pitch notation where middle C is C4 (MIDI note 60).
Period
The time it takes to complete one full wave cycle, in milliseconds. It's simply the inverse of frequency and is useful when setting delay or LFO times that need to sync to a pitch.
Wavelength (in Air)
The physical length of one sound wave cycle traveling through air at roughly room temperature (using 343 m/s as the speed of sound). Useful for acoustic and speaker design work, such as sizing bass ports or diagnosing room modes.
Real-World Example
MIDI note 60 is middle C. At the standard A4 = 440 Hz reference:
| MIDI note | Note name | Frequency | Period |
|---|---|---|---|
| 57 | A3 | 220.00 Hz | 4.545 ms |
| 60 | C4 (middle C) | 261.63 Hz | 3.822 ms |
| 69 | A4 (concert pitch) | 440.00 Hz | 2.273 ms |
| 81 | A5 | 880.00 Hz | 1.136 ms |
Notice that moving up exactly 12 semitones (one octave) always doubles the frequency — A3 to A4 to A5 goes 220 Hz → 440 Hz → 880 Hz.
Tips for Working with MIDI Pitch
- Middle C is MIDI note 60 in the most common convention, though some software labels it C3 or C5 instead.
- One octave equals 12 MIDI notes and always doubles or halves the frequency.
- Orchestras sometimes tune to A4 = 442 Hz or 443 Hz rather than 440 Hz — adjust the reference pitch field to match.
- Pitch bend and detuning move frequency continuously between semitones and aren't captured by whole MIDI note numbers alone.
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Last updated: August 2026 · Reviewed by: Simple Calculator Tools Editorial Team