What formula converts MIDI notes to frequency?

Frequency equals the A4 reference frequency multiplied by 2 raised to the power of (MIDI note minus 69) divided by 12.

How are cents calculated from frequency?

The cents difference is 1200 multiplied by log base 2 of the input frequency divided by the nearest note frequency.

Can I use A4 equals 432 Hz or 442 Hz?

Yes. Change the A4 reference field and every frequency and cents result will use that tuning.

Why does my DAW call MIDI 60 C3 instead of C4?

Octave labels are not consistent across manufacturers. The MIDI note number is unambiguous, so compare number 60 even if the displayed octave name differs.

Does this calculator send my notes or frequencies anywhere?

No. The conversion, copying, and CSV creation happen locally in your browser, and inputs are not uploaded or stored.

MIDI Note to Frequency Calculator — Notes, Hertz & Cents

Convert MIDI numbers or note names to equal-tempered frequencies, or turn a measured frequency into the nearest note and cents offset.

Pitch input

Convert from

MIDI note number Use a whole number from 0 to 127. MIDI 60 is middle C; MIDI 69 is A4.

A4 reference (Hz)

Note spelling

Your notes and frequencies stay in this browser. No pitch data is uploaded or stored.

Conversion result

Selected pitch A4 · 440.000 Hz Exact equal-tempered pitch at A4 = 440 Hz

Nearest noteA4

MIDI note69

Nearest note frequency440.000 Hz

Cents from nearest note0.00 cents

88-key piano positionKey 49 of 88

Wavelength at 20 °C0.780 m

MIDI 69 is inside the standard 0–127 note-number range.

Neighboring semitones

Note	MIDI	Frequency	From A4	Standard MIDI?

How to use the MIDI note and frequency calculator

Choose what you know. Select a MIDI number, a written note name, or a frequency in hertz.
Enter the pitch. MIDI input accepts whole numbers 0–127. Note names accept sharps or flats, such as F#3 or Bb4. Frequency input accepts positive decimal values.
Match the tuning reference. Leave A4 at 440 Hz for the common twelve-tone equal-tempered reference, or change it to match a session, orchestra, synthesizer, or sample library.
Read the cents offset. In frequency mode, 0 cents is exactly on the nearest equal-tempered note. A positive result is sharp; a negative result is flat.
Copy or export. Copy the current conversion, or download a five-note CSV table around the nearest semitone.

MIDI note to frequency formula

For twelve-tone equal temperament, with MIDI note 69 assigned to the selected A4 reference:

frequency = A4 × 2^((MIDI note − 69) ÷ 12)

At A4 = 440 Hz, MIDI 60 is 261.626 Hz, MIDI 69 is 440 Hz, and MIDI 72 is 523.251 Hz. Each increase of 12 MIDI numbers doubles the frequency.

Frequency to MIDI note and cents

exact MIDI value = 69 + 12 × log₂(frequency ÷ A4)
cents = 1200 × log₂(input frequency ÷ nearest note frequency)

The calculator rounds the exact MIDI value to find the nearest equal-tempered semitone. Cents then show the remaining pitch difference, normally from −50 to +50 cents. This is a mathematical pitch comparison; it does not detect a live microphone signal or decide whether a performance is musically in tune.

Assumptions

Twelve equal semitones divide every octave.
MIDI note 69 maps to the A4 reference entered in the calculator.
Scientific pitch notation is used for display, so MIDI 60 is C4.
Wavelength uses 343 m/s as a simple speed-of-sound reference at approximately 20 °C.
Microtuning tables, pitch bend, per-note tuning, stretch tuning, and instrument inharmonicity are not applied.

Why MIDI octave names can differ

MIDI note numbers are standardized integers, but octave labels vary among manufacturers and software. This calculator uses scientific pitch notation: MIDI 60 is C4 and MIDI 69 is A4. A DAW that calls MIDI 60 “C3” is referring to the same note number and pitch; only its displayed octave label is shifted.

When exchanging notes between devices, use the MIDI number as the unambiguous reference. The sharp/flat setting changes only the written enharmonic spelling—C♯ and D♭ have the same frequency in this equal-tempered calculation.

MIDI note frequency calculator FAQ

What frequency is MIDI note 69?

At the default A4 reference of 440 Hz, MIDI note 69 is exactly 440 Hz.

What MIDI note is middle C?

Middle C is MIDI note 60. This calculator displays it as C4, although some instruments and DAWs call the same MIDI note C3 or C5.

What is the formula for MIDI note frequency?

Use frequency = A4 × 2^((note − 69) ÷ 12). The A4 value is 440 Hz by default and can be changed.

How are cents calculated?

Cents equal 1200 × log₂(input frequency ÷ nearest note frequency). Positive cents are sharp and negative cents are flat relative to the nearest note.

Can I calculate with A4 at 432 or 442 Hz?

Yes. Enter any A4 reference from 300 to 500 Hz, and all note frequencies and cents offsets update immediately.

What happens above MIDI note 127 or below note 0?

Direct MIDI and note-name input stays within the standard 0–127 range. Frequency mode can identify an equal-tempered theoretical extension outside that range and labels it clearly as non-standard MIDI.