Guitar Tuner
Tune by microphone โ a cents needle and standard tuning targets.
About this tuner
Press start, allow the microphone, pluck one string at a time: the tuner shows the nearest note, the exact frequency, and a needle marking how many cents sharp or flat you are โ green at centre means within 5 cents, which is in tune by any practical standard. Detection is autocorrelation on this device; the audio never leaves your browser, and the mic stops the moment you press stop.
Tuning technique that actually helps
The standard targets are E2โA2โD3โG3โB3โE4 (82.4 to 329.6 Hz โ shown on the page). The two habits that make tuning stick: always tune up to the note โ if you're sharp, drop below and come back up, because approaching from below seats the string against the tuning post and it holds; and pluck near the twelfth fret with a light touch, since hard picking starts sharp and decays flat. New strings need re-tuning repeatedly for a day (they stretch); a string that won't settle is usually slipping at the post, not defying physics. The tuner reads anything pitched between 60 and 500 Hz โ bass, ukulele, violin, a hummed note โ and the tone generator supplies reference pitches for tuning entirely by ear, the skill this tool is happy to make obsolete. The metronome handles the other half of sounding good.
Frequently asked questions
How accurate is a microphone tuner?
Autocorrelation with sub-sample interpolation resolves pitch to about a cent in quiet conditions โ well beyond the ยฑ5 cents that counts as in tune. Background noise and very dead strings widen the wobble.
What are the standard guitar tuning frequencies?
E2 82.4 Hz, A2 110, D3 146.8, G3 196, B3 246.9, E4 329.6 โ low string to high, anchored to A4 = 440 Hz concert pitch.
Why should I tune up to the note?
Approaching from below keeps tension seated at the tuning post, so the string holds pitch. Tuning down to a note leaves slack that slips sharp-then-flat as you play.
Is my audio recorded or uploaded?
No โ pitch detection runs entirely in your browser, nothing is stored or sent, and the microphone turns off the moment you press stop (the browser's mic indicator confirms it).