Note finder — identify a music note from your microphone

What is a note finder?

A note finder is a music notes identifier: you sing, hum, or play one pitch, and it names that pitch. This note detector listens through your microphone, estimates the fundamental frequency, and writes the result in scientific pitch notation — a letter and an octave, such as C4 or F#3. Middle C is C4. The A above middle C is A4, defined as 440 Hz. Hertz and cents are shown too, so you can see both the name and how close the sound is to that exact pitch. It identifies one clear note at a time. It does not name the notes inside a chord, transcribe a full song, or read sheet music from a photo.

How a note is named

The identifier maps a live fundamental frequency onto the chromatic scale, then shows the octave used in written music.

1. Letter and octave, not only a frequency: The large readout is the note name in scientific pitch notation: C, C#, D, and so on, plus the octave number. A4 and A3 are the same letter an octave apart, at 440 Hz and 220 Hz.
2. One note at a time: The note finder follows a single sustained pitch. Pluck one string, press one piano key, or sing one vowel. A chord has several fundamentals, so the name will jump or lock onto the strongest one.
3. Hertz and cents under the name: The second line shows the measured frequency and the cents offset from the named note. Within 5 cents, the sound is effectively on that pitch. A larger offset means you are between two note names or still moving.
4. Voice, guitar, piano, and other melodic sources: Anything with a clear pitch in roughly 50–2000 Hz can be identified: singing, whistling, guitar, violin, ukulele, flute, or a single piano note. The on-page list includes middle C, concert A, and the two guitar E strings as checkpoints.
5. Naming happens in the browser: Audio is analyzed locally with the Web Audio API. Nothing is recorded or sent to a server.

How to identify a music note

Use a steady single pitch. The note name updates while that pitch holds.

1. 1. Start the note finder and allow the microphone: Click Start Note Finder and accept the permission prompt. The page needs the microphone to hear the pitch. It does not save the audio.
2. 2. Produce one note and hold it: Sing, hum, whistle, or play a single note for about a second. Avoid vibrato on the first try so the name can settle. If you are matching a sound from a speaker, put the microphone near that speaker and pause other noise.
3. 3. Read the note name and octave: The large text is the identified note, such as E2 or C6. Use the reference list if you want the standard frequency that belongs to that name. For tuning practice aimed at cents, the Pitch Detector page leads with the gauge.

When the note name is trustworthy

The name is only as stable as the pitch you give it.

1. Sharps are the spelling used here: Equal temperament uses one frequency for each black-key pitch. The finder spells those as sharps (C#, D#, F#, G#, A#), not flats. A#4 and Bb4 are the same frequency on this page.
2. Octave numbers follow middle C as C4: The number goes up when the pitch crosses from B to C. B3 is just below middle C. C4 is middle C. If a guitar string reads E3 instead of E2, it is an octave higher than standard low E.
3. Quiet the room: A fan, a second voice, or an open chord can pull the detected period off the note you intended. Identify notes one at a time.
4. Do not expect a transcription: A notes identifier for a live pitch is not a song transcription. Melody lines with fast note changes will flicker. Hold each pitch if you need a name you can write down.

Sources & References

References for how note names and concert pitch are defined.

• Scientific pitch notation

  “Scientific pitch notation (SPN), also known as American standard pitch notation (ASPN) and international pitch notation (IPN), is a method of specifying musical pitch by combining a musical note name (with accidental if needed) and a number identifying the pitch's octave.”

  The large readout uses that system. On this page, middle C is C4, and the octave number increases when the pitch moves from B to C. en.wikipedia.org/wiki/Scientific_pitch_notation

• A440 — concert pitch

  “A440 (also known as Stuttgart pitch) is the musical pitch corresponding to an audio frequency of 440 Hz, which serves as a tuning standard for the musical note of A above middle C, or A4 in scientific pitch notation.”

  Note names on this finder are calculated from A4 = 440 Hz, the ISO 16 reference. Every other note is a whole number of semitones away from that pitch. en.wikipedia.org/wiki/A440_(pitch_standard)

Frequently Asked Questions

Have questions? We have answers.

Related tools

Explore other diagnostic tools that pair well with this page.

• Pitch Detector→Pitch detector online—detect the pitch of any sound with your microphone. See note, frequency, and tuning accuracy.
• Voice Pitch Analyzer→Pitch analyzer online—find the note you are singing and see the octave and cents.
• Frequency Detector→Frequency detector online—measure a sound in hertz. Read Hz, the nearest note, and cents.
• Tone Generator→Tone generator online—play pure sine, square, triangle, or sawtooth tones from 20 Hz to 20 kHz for speaker and audio testing.
• Mic Test→Mic test online—check your microphone with live waveform and volume level.
• Harmonic Mixing Chart→DJ key chart online—look up Camelot codes, musical keys, and the codes that mix with them.