Does the tuner upload my audio?

No. Pitch detection runs entirely in your browser using the Web Audio API. The microphone stream stays on your device; nothing is uploaded. You can disconnect from the internet after the page loads and the tuner will keep working.

What instruments can I tune?

Any pitched instrument: guitar, bass, ukulele, violin, viola, cello, mandolin, banjo, harp, brass, woodwind, voice. The tuner is chromatic — it identifies whatever note it hears and tells you how many cents sharp or flat you are.

Why does the tuner need microphone permission?

To listen to your instrument. The browser asks for microphone access on first use; the audio never leaves your device. Denying permission means the tuner can't function.

Sub-cent accurate for clean, sustained tones from a quiet room. The autocorrelation pitch detector is robust against typical instrument noise but can struggle with very short notes (under 100 ms) or polyphonic input (chords).

What is A=440 Hz, and can I change it?

A=440 Hz is the standard concert-pitch reference for the note A above middle C. Some classical performers prefer A=442 Hz; baroque ensembles often use A=415 Hz. The tuner's reference is adjustable in the settings.

Tuner - Tune Any String Instrument

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Tap Start to listen

Idle

Reference pitches tap to hear by ear

Clamp to speaker octave

Tap a note to play a sustained sine. Tap again to stop. With Clamp on, all references play in the C4–C6 range so you can hear them on a phone speaker.

How to use

Pick your Instrument at the top — the string row appears below the note carousel. Tap a string to lock the target ; tap AUTO to snap to the nearest chromatic note instead.
Tap Start listening and allow microphone access. Pluck a string and the dial shows how many cents you're sharp (right) or flat (left). The needle goes green inside ±5 ¢ — that's "in tune".
The note carousel above the dial shows the current note plus its chromatic neighbours, so you can see which way the next note lies even before the cents settles.
A4 defaults to 440 Hz . Drop it to 415 for baroque pitch, or nudge to 442 / 444 for orchestral. Tuning swaps between Equal, Just (centred on C), and Pythagorean — set this for a-cappella or early-music sessions; leave on Equal otherwise.
No mic? Open the Reference pitches section and tap any note to play a sustained sine you can ear-tune against.