Music & audio
Musical note frequency
Find a note’s frequency and MIDI number with adjustable concert pitch.
A clear answer. Here’s how.
Uses twelve-tone equal temperament: frequency = A4 reference × 2^((MIDI note−69)/12). Accepts one sharp or flat and an explicit octave, including enharmonic octave crossings such as B#3=C4. Uses scientific pitch notation with middle C=C4 and MIDI note 60.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Note with octave
- A4
- A4 reference frequency (Hz)
- 440
Example result
- Frequency
- 440 Hz
- MIDI note number
- 69
- Canonical sharp spelling
- A4
- Canonical flat spelling
- A4