Note Frequency Converter
Find a note frequency or identify the nearest equal-tempered note. The reference is fixed at concert A4 = 440 Hz.
Twelve-tone equal temperament; A4 is fixed at 440 Hz.
A QUICK WALKTHROUGH
How to use this tool
- Choose a pitch class and octave to calculate its frequency.
- Or enter a frequency to find its nearest note.
- Read the cents offset from that nearest note.
Tuning model
Frequency = 440 × 2^((m − 69)/12), where m is the MIDI note number and A4 is m = 69. Enharmonic spellings use sharps in the result.
Input range
Note input covers MIDI notes 0–127. Frequency lookup accepts 8.176–12,543.854 Hz, the same range rounded at its endpoints.
GOOD TO KNOW
Common questions
Can I change the A4 reference?
No. This converter deliberately uses the fixed A4 = 440 Hz reference.
What does the cents value mean?
It shows how far the entered frequency lies above or below the nearest equal-tempered note; 100 cents equals one semitone.