Music Note Detector
What note is that? This music note detector tells you instantly. Sing, play, hum, or upload an audio file and see the musical note displayed in the biggest font possible. Cents deviation, interactive piano keyboard, reference tone playback, and note history. 100% browser-based, private, no downloads.
The detector uses the YIN algorithm — a widely-used monophonic pitch detection method that extracts the fundamental frequency from the autocorrelation of the audio waveform. Results are displayed in scientific pitch notation (e.g., A4, C#5) with the option to toggle between sharp and flat enharmonic equivalents. Whether you are checking your intonation as a singer, verifying a note on a fretted instrument, or transcribing a melody by ear, the cents deviation bar tells you exactly how close you are to equal temperament tuning. Because note recognition relies on a single clean fundamental, this tool also works as a note identifier to identify musical notes from a live microphone or uploaded file.
Music Note Detector Tool
How to Use the Music Note Detector
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Click Start Listening
Click "Start Listening" and allow microphone access. Select your preferred input device from the dropdown. All processing runs 100% locally in your browser -- nothing is uploaded.
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Play or Sing a Note
Produce a sound -- sing, hum, play an instrument, or whistle. The detector works best with single, sustained monophonic notes. For chords or complex audio, try the Frequency Detector. Singers can also use the Chromatic Tuner to check intonation against a specific target note during practice.
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Read the Giant Note Display
The detected note (e.g. C#4) appears in a massive display. The cents deviation bar shows how sharp or flat you are. The corresponding piano key lights up. Click Freeze to lock the display.
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Use Reference Tone & History
Click "Play Reference Tone" to hear the nearest correct note. Watch the note history stream for the last 20 detected notes. Click any piano key to hear that note. Export your session as CSV.
Frequently Asked Questions
What notes can this detect?
The Music Note Detector identifies notes from approximately C1 (32.7 Hz) to C8 (4186 Hz), covering the entire piano range and beyond. The 3-octave keyboard displays C3 to B5, but detection works across the full spectrum. It works with any pitched sound: voice, guitar, piano, violin, flute, trumpet, and more.
How accurate is the note detection?
The YIN pitch detection algorithm with parabolic interpolation achieves ±1–2 cents accuracy for clear, sustained tones. That is 1/100th of a semitone. For best results, use a close microphone in a quiet room and adjust the Sensitivity slider or use the Calibrate button to suppress background noise.
What is the difference between this and the Pitch Detector?
The Music Note Detector is focused on one thing: answering "What note is this?" with the biggest, clearest display possible. The Pitch Detector has more advanced features like pitch stability tracking, vocal range identification, target note mode, note streak gamification, and a scrolling pitch timeline. Use this tool for quick note identification; use the Pitch Detector for in-depth practice and analysis.
Can I upload an audio file instead of using the microphone?
Yes! Drag and drop any audio file (WAV, MP3, OGG, FLAC, M4A) onto the upload zone, or click to browse. The tool analyzes the file locally using an OfflineAudioContext and shows the dominant note. This is useful for identifying notes in recordings without needing a microphone. The file never leaves your browser.
What does the cents deviation bar show?
The cents bar shows how far the detected pitch is from the nearest perfect note. The center (0 cents) means perfectly in tune. Left means flat, right means sharp. The bar is color-coded: green for within ±5 cents (in tune), yellow for ±5–20 cents (close), and red for beyond ±20 cents (off). One cent is 1/100th of a semitone.
Is my audio data private?
Your audio is 100% private. All note detection runs entirely in your browser using the Web Audio API. No audio is recorded, stored, or transmitted to any server. The tool works completely offline once the page is loaded.
Can I use this to identify notes while singing or training my ear?
Yes — the Music Note Detector is ideal for ear training and sight-singing practice. Sing a pitch, read the detected note and cents deviation, then click "Play Reference Tone" to compare your voice against the perfectly-tuned reference. The note history stream is also useful for reviewing a short melodic phrase note by note. For comparing your voice against a specific target note during extended sessions, the Pitch Detector's target-note mode may suit you better.
Why does the detector sometimes jump between two notes?
Rapid switching between adjacent notes — called pitch jitter — usually happens when the played note falls close to the boundary between two semitones (i.e., the cents deviation is near ±50). Other causes include background noise, room reverb, or microphone pickup of harmonics. Clicking Calibrate suppresses ambient noise, and using the Freeze button locks the display once you are confident in the reading. Playing closer to the microphone and in a quieter environment also reduces jitter significantly.
What is A4 = 440 Hz, and can I use a different tuning standard?
A4 = 440 Hz is the international standard pitch (ISO 16:1975) and the reference this tool uses to map detected frequencies to note names. Some orchestras tune to A4 = 442 Hz or even 415 Hz for period-instrument performance. This tool always maps to 440 Hz equal temperament, so if your instrument is tuned to a different standard you may notice a consistent offset in the cents reading. To hear what any specific frequency sounds like at any tuning reference, try the online tone generator.
Does this work for identifying notes on guitar, bass, or ukulele?
Yes, for single-string plucked notes the detector works well with guitar, bass, ukulele, and similar fretted instruments. Hold the note for at least half a second so the YIN algorithm can lock on to the fundamental frequency. The tool identifies the note name and octave (e.g., E2 for the open low-E string on a standard-tuned guitar). For ongoing tuning rather than one-off note identification, the dedicated Guitar Note Identifier includes string-specific guidance and fret positions.
Related Tools
Pitch Detector
Advanced pitch analysis with piano keyboard, reference tone, stability tracking, vocal range, and target note mode.
Try it →Chromatic Tuner
Precision chromatic tuner for guitar, ukulele, violin, and any pitched instrument.
Try it →Guitar Note Identifier
Identify guitar notes and fret positions from sound with string-specific detection.
Try it →