🎸 Music Tools

Guitar Tuner

Tune by ear or by mic — guitar, bass, ukulele and violin, with cent-accurate readout.

Press Start to listen

Strings — tap to hear the reference pitch

Auto-detect stringOff: tune only against the string you tap

Play one string at a time, close to the mic, and let it ring. Nothing is recorded or uploaded.

Overview

Guitar Tuner: cent-accurate tuning in your browser

This tuner listens through your device's microphone and tells you exactly which note you played and how far it is from where it should be, measured in cents. Pluck a string and the needle swings: left means flat and you need to tighten, right means sharp and you need to loosen, and the display turns green once you hold the note within five cents of true. It detects which string you are playing automatically, so you can work through all six without touching the screen.

It handles far more than a six-string in standard tuning. Drop D, half-step down, Open G and DADGAD are built in, along with bass, ukulele and violin, and the reference pitch is adjustable from 415 to 466 Hz for ensembles that do not tune to A=440. If you prefer to tune by ear, tap any string to hear a clean reference tone. Everything runs locally — the microphone signal is analysed in your browser and never recorded or uploaded.

100% freeNo app neededMic or by earNothing uploaded
How to use it
  1. 1Choose your instrument and tuning from the dropdown.
  2. 2Press Start tuning and allow microphone access.
  3. 3Play one string at a time, close to the mic, and let it ring.
  4. 4Tighten if the needle sits left (flat), loosen if it sits right (sharp), until it locks green.
Key features
  • Cent-accurate pitch detection with automatic string recognition
  • Guitar standard, Drop D, half-step down, Open G and DADGAD, plus bass, ukulele and violin
  • Adjustable reference pitch from 415 to 466 Hz
  • Tap any string to hear a clean reference tone for tuning by ear
  • Live input-level meter and a hold-to-confirm in-tune indicator
  • Microphone processing disabled for accuracy — and nothing is recorded or uploaded

Frequently asked questions

How accurate is it?
It resolves pitch to within a few cents — a cent is one hundredth of a semitone, far finer than the ear can reliably judge. The display only confirms 'in tune' once the note stays within five cents for a moment, so a brief lucky reading doesn't count.
Why does the reading jump around when I strum?
Play one string at a time. Multiple notes at once give the detector several competing fundamentals. Also let the string ring rather than muting it quickly — the pitch settles a moment after the initial pluck.
What is the A4 reference setting for?
Most modern music tunes to A = 440 Hz, but orchestras often use 442 or 443, and period ensembles may use 415. Changing it shifts every string's target frequency to match.
Is my microphone recorded?
No. The audio is analysed frame by frame in your browser to measure pitch and is never stored or sent anywhere. Stopping the tuner releases the microphone entirely.