Pitch Detector

How to use the pitch detector

1. Click "Start Detection."

   Allow microphone access when your browser asks.

2. Sing or play a single, sustained note.

   A steady note gives a far more stable reading than a quick, short one.

3. Watch the note, Hz, and gauge.

   The needle leans left if you're flat, right if you're sharp, and centers when you're in tune.

4. Check the confidence indicator.

   A low reading means background noise or a weak signal — move closer to the mic and try again.

5. Watch the live history graph for stability.

   A flat, steady line means a stable pitch; a wobbly one usually means vibrato or drifting pitch.

What is pitch, and how does this work?

Pitch is how high or low a sound seems to us, and it maps directly onto frequency — how many times per second a sound wave repeats, measured in Hertz (Hz). A dog whistle is high frequency and high pitch; a boat horn is low frequency and low pitch. To hear a range of frequencies for yourself, our Tone Generator lets you play any exact frequency directly.

This tool listens through your microphone, and analyzes the resulting waveform using autocorrelation — comparing the wave against slightly delayed copies of itself to find the repeating pattern that reveals its fundamental frequency. That frequency is then matched to the nearest musical note and converted into a note name, an Hz value, and a cents deviation, dozens of times per second, which is what makes the gauge and graph feel live rather than delayed.

Understanding cents

A cent is 1/100th of a semitone — the smallest commonly used unit in music tuning, far finer than note names alone can express. Two people could both be "singing an A," but one might be 3 cents sharp and the other 40 cents sharp, and only the second one would sound obviously off to most listeners. As a rough guide, most people can start to notice pitch is "off" somewhere around 10–15 cents of deviation, which is why the gauge's centered "in tune" zone is deliberately narrow.

Who uses a pitch detector, and why

Singers and vocal students use it for real-time feedback on intonation, building the muscle memory to land a note accurately without needing to hear it played first. Instrumentalists use it the same way a clip-on tuner works, but without needing separate hardware — useful for anything from a violin to a trombone to a single guitar string. Choir directors and section leaders use it to spot a singer who's consistently drifting sharp or flat during rehearsal. And plenty of people simply use it for ear training, checking how close they can get to a target pitch by voice alone before verifying against the tool.

Reading the live history graph

The scrolling line beneath the confidence bar is tracking your cents deviation over the last few seconds, giving you a sense of pitch stability that a single number can't show on its own. A flat, steady line sitting right on the centre mark means you're holding a genuinely stable pitch. A line that drifts steadily in one direction usually means you're sliding sharp or flat over the course of a held note — common when breath support fades near the end of a phrase. A regularly wobbling line, rising and falling in a repeating pattern, is what vibrato looks like graphed out, which is completely normal for a sustained note sung with intentional vibrato rather than a sign of poor pitch control.

Watching this graph over a few repeated attempts at the same note is also a fast way to see whether you're improving — a newer attempt that wobbles less, or drifts less, than an earlier one is genuine, visible progress.

Monophonic vs. polyphonic pitch detection

This tool, like virtually every browser-based pitch detector, is built for monophonic input — one clear pitch at a time. That covers the overwhelming majority of real use cases: a single voice, a single instrument playing one note, or one string of a guitar picked on its own.

Polyphonic input — multiple distinct pitches sounding together, like a strummed chord or a full band recording — is a fundamentally harder problem that autocorrelation-based methods like this one aren't designed to solve. Feeding a chord into this tool won't produce a useful reading; it may lock onto one of the notes, jump between them, or show a low confidence score. If you need to identify a full chord, that calls for different, more specialized software entirely.

Common note frequencies

Instrument tuning references

If you're using this to tune an instrument rather than your voice, here are the standard open-string frequencies for two common ones.

Fixing common pitch detection problems

The reading jumps around or won't settle. Try singing or playing a bit louder and holding the note steady — short, quiet, or rapidly changing notes are the hardest input for any pitch detector to lock onto.

The octave looks wrong. Very low or very high voices can occasionally have a strong overtone mistaken for the fundamental note. This is a known limitation of simple pitch detection rather than a sign anything is broken — try adjusting your volume or moving closer to the mic.

Confidence stays low. Reduce background noise, move closer to your microphone, and make sure only one note is sounding at a time — chords and overlapping notes confuse any monophonic pitch detector.

Nothing happens at all. Check that microphone access was actually granted — look for a blocked-microphone icon in your browser's address bar, and confirm the correct input device is selected in your system sound settings.

More tools on ProDeviceTest

Testing a whole audio setup rather than just pitch? These run the same way — instant, no download, right in your browser.

• Tone Generator — play any exact frequency in sine, square, sawtooth, or triangle waves
• Mic Test — check your microphone with a live waveform
• Voice Recorder — record, trim, and download audio
• Sound Test — check left/right channels and a full frequency sweep
• All Music Tools — the full category