Online Guitar Tuner with Microphone

How to tune your guitar with this tuner

1. Press Start tuner and allow microphone access when the browser asks. A laptop or phone microphone is fine, but get the guitar within a metre or so of it.
2. Choose your tuning. Most songs use Standard (E A D G B E).
3. Pluck one open string and let it ring. Don't strum all six strings — the tuner can only follow one note at a time.
4. Read the note name and the needle. If the reading says flat, the string is too low: tighten it slowly. If it says sharp, loosen it.
5. When the needle sits in the green middle and the note turns green (within ±5 cents), move to the next string.

Standard tuning, string by string

Strings are numbered from the thinnest (1) to the thickest (6). Many players remember the open notes from low to high with a phrase such as Eddie Ate Dynamite, Good Bye Eddie.

What “cents” mean

A semitone — the distance between two neighbouring frets — is divided into 100 cents. A string reading −20 cents is a fifth of a semitone flat. Most people can't hear a difference of under 5 cents on a single note, but they can hear it when two slightly out-of-tune strings are played together as a chord, as a slow “wobble” or beating. That is why a chord can sound sour even when every string looks “nearly right”.

How the tuner works

The page uses the Web Audio API built into your browser. It reads short slices of audio from the microphone and runs an autocorrelation pitch detector: it compares the waveform with delayed copies of itself to find the repeating period, which gives the fundamental frequency. That frequency is converted to the nearest note and the distance from it in cents. All of this happens on your device; no audio is sent anywhere.

Alternate tunings included

• Half step down — every string lowered one semitone. Popular in rock and with singers who want a slightly lower key; also slightly easier on the fingers.
• Drop D — only the low E is lowered to D, giving one-finger power chords and a deep drone for songs in D.
• DADGAD — a modal, open-sounding tuning used in Celtic and fingerstyle playing.
• Open G and open D — strumming the open strings gives a full major chord. These are the classic slide-guitar tunings.
• Ukulele (G C E A) and 4-string bass (E A D G).

Tuning by ear with the reference tones

If your microphone isn't available, tap a string button to hear its target note for about two seconds, then pluck the string and adjust until the two sounds merge into one steady tone. When they're close but not equal you'll hear a pulsing “wah-wah-wah”; the slower the pulse, the closer you are. You can also use the classic fifth-fret method explained in our full tuning guide.

Why won't my guitar stay in tune?

New strings stretch for the first few days, so they drift flat constantly. Gently pull each string away from the fretboard along its length, retune, and repeat two or three times. Temperature and humidity changes, worn tuning pegs and a poorly cut nut are other common causes. If the open strings are in tune but chords high up the neck sound off, the guitar's intonation may need adjusting by a technician.

Frequently asked questions