Note Frequency & MIDI Calculator
Find the frequency. Name the pitch. Set a tuning value.
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Default reference: A4 tuned to 440 Hz
| Quantity | Value |
|---|---|
| Note | A4 |
| Frequency | 440 Hz |
| MIDI number | 69 |
| Cents from nearest note | 0 cents |
Convert a note, MIDI number or frequency
Start with A4 at 440 Hz, MIDI note 69. Choose a note and octave, enter a MIDI number, or supply a frequency to find its nearest note. This is an immediate numeric reference, rather than a scale lesson or a sound-design exercise.
The calculator uses twelve-tone equal temperament and a stated A4 reference, adjustable from 400 to 480 Hz. For MIDI number m, frequency is A4 reference times 2 to the power of ((m minus 69) divided by 12). One octave doubles frequency; one semitone multiplies it by the twelfth root of two.
Read cents and octave labels correctly
A frequency can fall between named notes. Cents report its distance from the nearest note at your chosen tuning: positive means higher, negative means lower, and 100 cents is one equal-tempered semitone. At an exact halfway point, the calculator chooses the higher note. Supported nearest-note results stay within MIDI 0 to 127.
Scientific pitch notation makes middle C C4, MIDI 60. Some music software gives that same MIDI note a different octave label, so compare the MIDI number as well as the name. Hear reference plays a quiet one-second tone at the entered frequency, not a microphone recording or an automatic pitch measurement.
Calculate a shift without processing a sample
Optional pitch-shift calculations compare known notes or frequencies. Playback-rate ratio and semitones describe a linked change in speed and pitch. They supply settings for compatible music software; this page does not retune an audio file or preserve its duration.
Harmonic frequencies are whole-number multiples of a fundamental. The theoretical beating rate for two nearby steady tones is their absolute frequency difference: 440 Hz and 442 Hz differ by 2 Hz. That number is not a guarantee of what a complex sound or your speakers will make audible. All lookups happen in your browser, without an upload, microphone access or an account.
Common questions
What frequency is A4, and what is its MIDI number?
At the default tuning A4 is 440 Hz and MIDI 69, with zero cents from the reference note. Changing the A4 tuning changes its frequency while its MIDI number stays 69.
Can this detect the pitch of my voice or a sample?
No. You supply notes, MIDI numbers or Hz. It does not listen, request microphone access, upload a file or detect the pitch of recorded audio.
What does a negative cents value mean?
The entered frequency is lower than the displayed nearest note at the chosen A4 tuning. Cents measure a frequency ratio, so a fixed number of cents is not a fixed number of Hz.