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Map any MIDI note number to its note name and frequency, and back again. Covers 0-127 and C-1 to G9, with the A4 reference adjustable from 380 to 500 Hz.

📘 How to Use

  1. Pick the conversion direction (Number to Name or Name to Number)
  2. Type a MIDI note number or a note name (e.g. A4, C#3, Bb5)
  3. Adjust the A4 reference pitch between 380 and 500 Hz if needed
  4. Read the note name, frequency, octave and pitch class results

MIDI Note Number Converter

0-127
Hz

※ Frequency formula: f = A4 × 2^((n − 69) / 12)

※ Octave naming follows the MIDI standard C-1=0, A4=69

MIDI note number
—
Note name
—
Frequency
— Hz
Octave
—
Pitch class
—
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MIDI Note Number Converter｜Map Numbers, Names and Frequencies Both Ways

Convert MIDI note numbers to note names and back, with the frequency, octave and pitch class shown for every note. It covers the full 0-127 range anchored on A4=69, and the A4 reference is adjustable from 380 to 500 Hz.

💡 About this tool

When you live in a DAW or a synth manual, you constantly need to answer small questions fast: is piano-roll "60" a C, and what pitch is "note 69" in this sampler's docs? MIDI note numbers are integers from 0 to 127, with A4 (concert A) fixed at 69. This converter works in either direction in a single step, so you can go number to name or name to number without hunting through a chart.

Frequency uses the equal-temperament formula f = A4 × 2^((n − 69) / 12). Because the A4 reference is adjustable, you can read real frequencies at orchestral tunings like 442 Hz or historically-informed Baroque pitch around 415 Hz, not just the default 440 Hz. Name input accepts both sharp (C#3) and flat (Bb5) spellings, and results are returned in sharp spelling.

🧐 Frequently Asked Questions

Is MIDI note 60 C3 or C4? Octave labelling is a known split. This tool uses Scientific Pitch Notation, where A4=69 and middle C (60) = C4, so the range runs C-1=0 to G9=127. General MIDI and some makers (the Yamaha lineage) label that same 60 as C3, which makes their octave numbers sit one lower than ours. The underlying number (60) is universal, so working by number sidesteps the mismatch entirely.

What does changing the reference pitch do? It scales every note's frequency uniformly. Set A4 to 442 Hz and note 69 (A4) reads 442 Hz, with all other notes shifting by the same ratio. The number, name and octave do not depend on the reference, so those stay put.

What input range is allowed? Numbers must be integers from 0 to 127. Note names span C-1 (number 0) through G9 (number 127); anything outside that triggers an error message.

Can I type flats like Bb? Yes — input accepts both flats (Db, Eb, Gb, Ab, Bb) and sharps. Output note names are normalised to sharps (C#, D# …) for consistency.

📚 Why the octave labels disagree

The MIDI spec only declares that note number 60 is "a C"; it never says which octave that C belongs to. Manufacturers filled the gap differently: the Roland convention treats 60 as C4 while Yamaha treats it as C3, and a few followed Yamaha's lead. The middle-C pitch itself is about 261.63 Hz (at A4=440 Hz) everywhere — only the label shifts by one octave. That ambiguity is exactly why exchanging note numbers, rather than names, keeps two pieces of gear in agreement.