Why does the reading jump around or not show anything?

Usually the room is noisy, several strings are ringing at once, or the device is too far away. Play one string at a time, mute the others with your hand, hold the phone or laptop near the sound hole or bridge, and wait half a second for the needle to settle before turning the peg. For low bass notes, pluck closer to the bridge so the harmonics are clearer.

What is a cent, and how close is in tune?

A semitone is divided into 100 cents. The tuner shows In tune when you’re within ±3 cents, which is below the roughly 5-cent difference most people can hear. Within ±15 cents the needle turns amber, and beyond that it turns red.

What’s the difference between A4 = 440, 442 and 432 Hz?

A4 is the reference every other note is tuned from. 440 Hz is the international standard; many orchestras use 442 or 443 Hz for a brighter sound, and baroque ensembles often use 415 Hz, about a semitone lower. When you play with others, everyone needs the same A4, or every note will be uniformly sharp or flat.

Does it work on my phone? Is my audio recorded?

Yes, it works in current mobile browsers on iPhone and Android over HTTPS once you allow the microphone. Audio is analyzed in real time inside your browser — it is never recorded, stored or uploaded, and the microphone is released as soon as you press Stop or close the page.

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🎸Online Tuner - Guitar, Ukulele, Violin & Bass Mic Tuner

Open the page, allow the microphone, pluck an open string and see which note it is, whether it’s sharp or flat and by how many cents. Pitch detection runs entirely in your browser: the YIN algorithm finds the fundamental, then the harmonic energy of the whole frame refines it to within a cent, while a stability gate and median smoothing keep the needle calm. It reads everything from a 5-string bass’s low B (about 31 Hz) to a violin’s E string. Built-in tunings cover guitar (standard, Drop D, half step down, Open G, Open D, DADGAD, Drop C), 4- and 5-string bass, ukulele (high G, low G, baritone), violin, viola, cello and the 21-string guzheng, plus a chromatic mode for any note. The tuner detects which string you’re playing automatically, or you can lock it to one string. Set the A4 reference anywhere from 415 to 466 Hz (baroque 415, orchestral 442/443, 432 Hz), and click any string to hear a reference tone and tune by ear. Choose a needle or a strobe display — the strobe stands perfectly still when you’re in tune, so tiny deviations are easy to see. Browser noise suppression, auto gain and echo cancellation are switched off so they don’t disturb detection, and audio is analyzed on your device only, never recorded or uploaded.

Free · No sign-up · Runs in your browserLast updated: 2026-10-26

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How to use Online Tuner

1Choose your instrument and tuning, and adjust A4 if needed
2Click Start tuning, allow the microphone and pluck one open string
3Tighten or loosen the peg as prompted until the needle is centered and shows In tune, then move to the next string

FAQ

Why does the reading jump around or not show anything?: Usually the room is noisy, several strings are ringing at once, or the device is too far away. Play one string at a time, mute the others with your hand, hold the phone or laptop near the sound hole or bridge, and wait half a second for the needle to settle before turning the peg. For low bass notes, pluck closer to the bridge so the harmonics are clearer.
What is a cent, and how close is in tune?: A semitone is divided into 100 cents. The tuner shows In tune when you’re within ±3 cents, which is below the roughly 5-cent difference most people can hear. Within ±15 cents the needle turns amber, and beyond that it turns red.
What’s the difference between A4 = 440, 442 and 432 Hz?: A4 is the reference every other note is tuned from. 440 Hz is the international standard; many orchestras use 442 or 443 Hz for a brighter sound, and baroque ensembles often use 415 Hz, about a semitone lower. When you play with others, everyone needs the same A4, or every note will be uniformly sharp or flat.
Does it work on my phone? Is my audio recorded?: Yes, it works in current mobile browsers on iPhone and Android over HTTPS once you allow the microphone. Audio is analyzed in real time inside your browser — it is never recorded, stored or uploaded, and the microphone is released as soon as you press Stop or close the page.