Online guitar tuner

How to tune your guitar in 6 steps

1. Allow microphone access. The sound is analyzed on your device: nothing is recorded or sent anywhere.
2. Find a quiet spot and hold the phone about 20 cm (8 inches) from the soundhole (acoustic guitar) or the amp (electric guitar).
3. Pluck a single open string firmly, then let it ring. The tuner automatically picks the closest string; tap a string on screen to lock it if you prefer.
4. If the needle is to the left, the string is flat: tighten it. If it is to the right, loosen it slightly below the note, then bring it back up.
5. Stop when the indicator is centered and turns green, then move on to the next string.
6. Go through all six strings a second time: tightening one string slightly changes the tension on the neck and pulls the others out of tune.

Notes and frequencies

Standard tuning notes

From the lowest string to the highest, a guitar is tuned E, A, D, G, B, E. The low string is E2 at 82.41 Hz and the thinnest string is E4 at 329.63 Hz, two octaves higher. The open A string vibrates at 110 Hz, two octaves below the A4 = 440 Hz reference.

The key thing to remember is that the two outer strings share the same note, two octaves apart. The table below gives the exact frequency of each string in standard tuning and in a few common alternate tunings.

Which way should I turn the tuning pegs?

It is the most common beginner question, and the answer depends on the headstock. On a 6-in-line headstock, typical of many electric guitars, every tuner tightens the string in the same direction. On a 3+3 headstock, with three tuners on each side, the two sides are mirror images: the motion that tightens a low string loosens a high one.

The rule that never fails: the string must wrap further around the post to go up in pitch. The tuner shows a headstock diagram matching your guitar and, while you turn, it watches whether the note rises or falls to confirm you are going the right way.

Good habits for tuning that holds

• Always tune up to the note: start slightly below, then tighten. This takes up the slack in the gears and the friction at the nut, so the string stays put.
• One string at a time: never turn a peg without knowing which string it belongs to; follow the string with your finger up to the post.
• New strings stretch for several days. Retune often at first, and gently pull each string upward to settle it.
• Watch out for the octave: a string tuned an octave too high is very likely to snap. The tuner warns you about an abnormally tight string before it is too late.

Alternate tunings and capo

Instrument mode offers nearly 70 tunings: half a step down (E♭), drop D, D standard, drop C, open G, open D, DADGAD, Nashville tuning, 7- and 12-string guitar, and more. When you switch from one tuning to another, the app warns you if some strings need to go up, because that is when strings break. If you play without changing the setting, it can also notice that your low string is on D and suggest drop D.

Playing with a capo? Enter the fret (1 to 12): the target notes shift accordingly, so you can check your tuning without removing the capo. You can also create your own tuning and share it with a simple link.

How accurate is a microphone tuner?

On a real guitar, a phone microphone gives an accuracy of around ±2 to 3 cents. That is below what the ear can tell apart on a single note, about 5 cents. The tuner ignores the attack, the instant right after plucking when the string sounds a little sharp, and measures the note once it has settled.

For a quick check before playing, a beta mode analyzes all six strings strummed together and points out any string that is more than 5 to 10 cents off. For fine tuning, go back to string-by-string tuning, or to guided mode, which walks you from one string to the next.