Guitar tuner

Standard guitar tuning, from the 6th string to the 1st: E A D G B E. Frequencies are for A4 = 440 Hz.

Other tunings on this tuner

Tune one string at a time. Pluck a single open string, let it ring and read the note, the needle and the cents. A minus value with the hint Tune up means the string is flat, so tighten it; a plus value with Tune down means it is sharp, so loosen it. The string is done when the needle stays inside the green zone, within 5 cents of the note.

Finish every string by tuning up to the note, not down to it. If a string is sharp, loosen it until it sits a little below the target, then bring it back up. The last movement then tightens the string against the gear, and it keeps its pitch instead of slipping flat after a few minutes of playing.

When all six are done, go around once more. Each string you tighten pulls on the neck, so the first strings may have moved a little, especially with new strings or a floating tremolo bridge. The second pass usually takes seconds.

Strings are numbered from the thinnest, the 1st (high E), to the thickest, the 6th (low E), and the string buttons run like a tuning chart, 6th string first. To find the right peg, follow the string past the nut to the post it wraps around. On a six-in-line headstock the low E peg is the one closest to the nut; on a three-a-side headstock the three thick strings share one side and the three thin ones the other.

Turn in small steps and pluck again after each one: the thin strings react to the slightest movement. There is no fixed rule for which way to turn, because it depends on the side of the headstock the peg is on. If the needle moves away from the center, you are turning the wrong way.

A string that is far off, such as a new string that starts several notes low, can be taken for its neighbor. Tap that string's button instead: you hear its note, and the tuner stays locked on that string until you tap Auto.

All three use the same standard tuning, E A D G B E, and the frequencies in the chart above apply to each of them. What differs is how you get a clean reading and what makes each one drift.

• Acoustic: point the phone at the sound hole. Wood and steel strings react to heat and humidity, so give a guitar that comes in from a cold car a few minutes before you tune it.
• Electric: unplugged, it is quiet, so keep the phone close to the strings, or play through the amp with a clean sound. Distortion and effects add overtones that make any tuner jumpy. On a floating tremolo every string you tune shifts the others, so go around several times.
• Classical: nylon strings keep stretching for days after they are fitted and go flat again and again. Tune, play for a while and tune again until they settle.
• Any guitar: if the open strings are right but chords high on the neck sound sour, the problem is intonation, not tuning. Compare the note at the 12th fret with the open string on the chromatic tuner; it should be the same note an octave up. On an electric the bridge saddles adjust it; on an acoustic it is a job for a repair shop.

Every string button plays a plucked reference note, and that works even when the browser has no microphone access. Tap a button, pluck the same string on your guitar and turn the peg until the two sounds merge. While they differ you hear a wobble, and it slows down as you get closer.

Once the low E is right, the classic cross-check uses the 5th fret: the 6th string pressed at the 5th fret gives the note of the open 5th string, A, and the same works from the 5th string to the 4th and from the 4th to the 3rd. Between the 3rd and 2nd strings use the 4th fret, then the 5th fret again from the 2nd string to the 1st.