What formula converts Hz to a note name?

Using equal temperament with A4 as the reference: MIDI = 69 + 12 × log₂(f / A4). Round the result to the nearest integer for the closest note. The cents deviation is (MIDI_exact − MIDI_rounded) × 100.

What does "cents" mean in this context?

A cent is one hundredth of a semitone. There are 1200 cents in an octave. A deviation of +50 cents means the frequency is exactly halfway between two adjacent notes (a quarter tone sharp). Human pitch perception threshold is roughly 5–10 cents.

What is the range of supported frequencies?

The tool supports frequencies from about 8 Hz (MIDI note 0, C−1) up to around 12,544 Hz (MIDI note 127, G9). Values outside this range are flagged as out of MIDI bounds.

Why do I need to choose a tuning reference?

The note name assigned to a frequency depends on the pitch of A4. At 440 Hz (modern standard), 432 Hz (alternative/Verdi), 415 Hz (Baroque), or 444 Hz (high concert), the same frequency maps to slightly different note positions and cents deviations.

What is the difference between MIDI note 60 and middle C?

MIDI note 60 is universally defined as middle C, also called C4. Its frequency at A4 = 440 Hz is exactly 261.626 Hz.

Frequency to Note Converter

Enter a frequency in Hz to instantly find the nearest musical note, its MIDI number, and how many cents sharp or flat it is.

Frequency Input

Frequency (Hz)

Tuning Reference (A4)

Quick Examples

Nearest Note

-50 cents 0.0 cents +50 cents

Exact — 0 cents deviation

Input Frequency 440.000 Hz

Exact Note Frequency 440.000 Hz

MIDI Note 69

Tuning Reference A4 = 440 Hz

Nearby Notes (±3 semitones)

Note	Frequency (Hz)	Cents from Input

Done!

Summary

Enter a frequency in Hz to instantly find the nearest musical note, its MIDI number, and how many cents sharp or flat it is.

How it works

Type any frequency value in Hz into the input field.
Choose a tuning reference — A4 = 440 Hz is the modern concert standard.
The nearest musical note name, octave, and MIDI number appear immediately.
The cents deviation shows how many cents sharp (+) or flat (-) the input is from the exact note.
Click Play Tone to hear a sine wave at your entered frequency.
Click the nearest-note name to hear that exact note for direct comparison.

Use cases

Identify the pitch of a recorded sound by its frequency.
Tune instruments or verify electronic tuner readings.
Find the exact MIDI note number for a given Hz value in DAW work.
Check how close a synthesizer oscillator is to a target pitch.
Explore microtonal intervals and cents deviations from equal temperament.
Verify that audio equipment is outputting the correct test tone pitch.
Learn the relationship between Hz values and musical notation.
Compare historical tuning systems by entering their reference frequencies.

Frequently Asked Questions

Last updated: 2026-09-22 · Reviewed by Nham Vu