How this guitar tuner works
Tap Start, allow the microphone, and play one string at a time. The tuner listens through your mic, works out the pitch with autocorrelation detection, and shows the nearest string of your chosen tuning together with how many cents sharp or flat you are. The needle settles like a real spring, and when you hold within 5 cents of the target it locks green and plays a soft confirmation chime, so you can tune without staring at the screen.
It works with anything the microphone can hear: acoustic guitar, electric through an amp, or an unplugged electric held close to the mic. A quiet room helps, and tuning up to the note (loosen slightly, then tighten into pitch) keeps the string stable once it locks.
Supported tunings
Standard (E A D G B E), Drop D, Eb standard, Open G and Open D. Pick the tuning above the gauge and each string's target note and frequency update with it.
Common questions
Is a microphone tuner accurate enough?
For tuning a guitar, yes. The readout shows cents (hundredths of a semitone) and the in-tune band is plus or minus 5 cents, tighter than most people can hear. A clip-on or pedal tuner only wins in loud environments where the mic picks up too much noise.
Is it really free?
Yes. The tuner is free, needs no account and has no usage limit. It is part of Neural-Fretboard, a browser guitar app with a player, a 3D guitar and a chord library, all free, plus a Creator practice mode that listens to you play.
Why does it ask for microphone permission?
Pitch detection needs to hear the string. The audio is analyzed live in your browser and never recorded or uploaded. Mic access also requires a secure HTTPS connection, which this site always uses.
The needle jumps around. What helps?
Background noise and ringing open strings are the usual causes. Mute the other strings with your palm, pluck once firmly rather than repeatedly, and let the note ring while the needle settles.
In tune? Look up a chord in the chord library or load a song in the player and play along.