Local · Private · Free

Guitar Tuner

A chromatic tuner for guitar, bass, ukulele and violin. Pitch is detected from your microphone entirely on your device, no audio is ever uploaded. Free, instant, no signup.

The tuner isn’t available here

Your browser doesn’t support microphone capture (getUserMedia) or the Web Audio API. Try the latest Chrome, Edge, Firefox, or Safari. Note: the microphone requires a secure context (https or localhost).

Microphone permission was denied

The tuner needs your microphone to hear the instrument, the audio is analyzed locally and never recorded or sent anywhere. Allow microphone access for this site in your browser’s address-bar permissions, then try again.

Ready to tune

Click below and allow microphone access. Your browser will analyze the sound in real time using autocorrelation, nothing is recorded or uploaded.

All pitch detection happens locally in your browser, even offline.

● LIVE, listening

listening…

, Hz

Instrument preset

A4 calibration, 440 Hz

The string nearest to what you’re playing lights up; it turns green when you’re within ±5 cents.

How it hears your pitch

The tuner reads the raw waveform from your microphone and runs autocorrelation, sliding the signal against itself to find its repeating period, with parabolic interpolation for sub-sample precision and a clarity threshold so noise doesn’t fake a reading. It compares the result to the nearest equal-temperament note (using your A4 calibration) and shows the offset in cents. All of it runs ~30 times a second, locally, with no servers involved.

About Guitar Tuner

Guitar Tuner is a free, private browser tool by Digital Heroes. It listens to your instrument through your microphone and detects pitch in real time using autocorrelation. Everything runs locally on your device. Your audio is never uploaded to a server, there is no sign-up required, and the tool works offline once the page has loaded. Supports guitar, bass, ukulele and violin, with standard and drop tunings, plus an A4 calibration slider from 432 Hz to 446 Hz.

What you can do

Tune guitar in standard or Drop D with live needle feedback and a cents readout.

Switch to bass, ukulele, or violin presets to highlight the correct target strings.

Use chromatic mode to detect any note across the full musical range.

Calibrate A4 from 432 Hz to 446 Hz to match an orchestra or recording session.

See cents offset on a visual gauge that turns green when you are within 5 cents of pitch.

Copy your reading (note name, Hz, and cents offset) to the clipboard in one click.

How to use Guitar Tuner

Open Guitar Tuner in your browser. No signup or installation needed.

Click Enable microphone and allow access when your browser asks.

Pick your instrument preset (guitar, bass, ukulele, violin, or chromatic) and adjust A4 calibration if needed.

Play a string. The needle and cents display update in real time. Tune until the gauge turns green.

Optionally click Copy reading to save the note name, Hz, and cents offset to your clipboard.

Frequently asked questions

Is Guitar Tuner free?

Yes. Guitar Tuner is completely free for everyone. No sign-up, no account, and no usage limits.

Is it private? Is my audio uploaded anywhere?

No. Guitar Tuner runs entirely in your browser. The microphone signal is analyzed locally and never sent to a server.

Does it work offline?

Yes. Once the page has loaded, the tuner keeps working with no internet connection. You can also install it as an app from your browser for quick access.

Do I need to install anything or create an account?

No. Just open the page, allow microphone access, and start tuning. No downloads, no accounts.

What instruments does it support?

It supports standard guitar (E A D G B E), Drop D guitar, ukulele (G C E A), bass (E A D G), and violin (G D A E). Chromatic mode detects any note from roughly 25 Hz to 2200 Hz.

What is A4 calibration and when do I need it?

A4 calibration sets the reference frequency for A above middle C. The default is 440 Hz. Some orchestras and recordings use 432 Hz or 442 Hz. Adjust the slider to match your ensemble.