MIDI Note Number Converter
Look up MIDI numbers, scientific pitch names, and equal-tempered frequencies locally.
Uses C4 = 60 and A4 = 440 Hz.
A QUICK WALKTHROUGH
How to use this tool
- Enter a MIDI number or note name such as C4, A#3, or Eb5.
- Convert to see the matching number, name, and frequency.
- Copy both results if needed.
Standard convention
MIDI numbers 0–127 map to C-1 through G9. Note names use scientific pitch notation with C4 = MIDI 60 and A4 = MIDI 69 at 440 Hz.
Equal temperament formula
Frequency is 440 × 2^((MIDI − 69) / 12). Each semitone is one twelfth root of two apart. Frequencies display to two decimal places.
Names and local processing
Sharp and flat spellings are accepted, including C#, Db, A#, and Bb. Enharmonic spellings resolve to the same MIDI number. Processing is local and no audio or network request is involved.
GOOD TO KNOW
Common questions
Why is MIDI 60 C4?
This uses the C4 = 60 scientific pitch convention; some older software uses C3 = 60.
Are flats accepted?
Yes. Flats such as Eb4 and Bb2 map to their enharmonic sharp equivalents.
What range is valid?
Only integer MIDI numbers 0 through 127 are valid.