How to use a clip-on tuner, including the bit nobody explains

Clip the tuner to the headstock, switch it on, play a string, and it shows you a letter and a needle. That much is obvious. What is not obvious, and what causes most first-week frustration, is which way to turn the peg — and turning the wrong way under tension is how beginners snap strings.

The six notes, from thickest to thinnest

Standard tuning, thickest string to thinnest: E, A, D, G, B, E. The thickest string is the one nearest your face when you hold the guitar in playing position, and it is the low E. The thinnest, nearest the floor, is the high E.

A chromatic tuner — which every tuner on this site is — shows you whichever note is nearest to what you played, not the note you were aiming for. If you play the low E and the tuner says D, the string is badly flat and needs tightening a long way. If it says F, it is sharp and needs loosening.

Which way to turn the peg

There is no universal rule, because it depends on which side of the headstock the peg is on and how the string is wound. Here is the method that always works:

1. Play the string and watch the tuner needle.
2. Turn the peg a small amount in either direction.
3. Play the string again. If the needle moved toward the middle, keep going that way. If it moved further out, go the other way.

The important word is small. A quarter turn is a lot. If you turn half a turn and the pitch has not moved at all, stop — the string may not be seated properly at the bridge, or you may be turning the peg for a different string, which is a genuinely common mistake on a headstock with three pegs a side.

Always arrive from below

Tune up to the note, not down to it. If you overshoot and go sharp, drop the string clearly flat and come back up.

The reason is mechanical. A string passes over the nut and, on many guitars, through a slot that grips it slightly. When you tune down, tension released at the peg does not fully equalize across the nut, so the string sits in a temporarily unstable state and slips sharp again after a few strums. Arriving from below leaves the string under consistent tension and it stays put.

New strings will not hold, and that is not a fault

A freshly fitted set stretches for the first few days. You will tune it, play four chords, and find it flat again. This is normal.

You can speed it up: after tuning, gently pull each string upward away from the fretboard along its length — an inch or so of lift, no more — then retune. Repeat two or three times. The string arrives at its settled length faster.

If one string keeps going flat while the others hold, the winding at the tuning post is slipping. The fix is to restring that one properly rather than to keep tuning it. See how to change guitar strings.

Where to clip it, and why the reading jumps

Anywhere flat and rigid on the headstock, front or back. Avoid clamping across a tuning machine, which moves, or over the nut.

If the reading jumps around, three usual causes: the clip is loose; another string is ringing sympathetically (mute the others with your palm); or you are plucking too hard, which makes the pitch sharp for the first fraction of a second before settling. Pluck moderately and read the tuner after the attack has passed.

Calibration, and why not to touch it

Tuners let you change the reference pitch — the frequency assigned to A above middle C. Standard is 440 Hz. Snark publishes a range of 415–466 Hz on the ST-8; Korg publishes 410–480 Hz on the MA-2 metronome's reference tone.

Leave it at 440. Every recording you play along with, every other instrument you meet, and every backing track assumes it. The only reasons to change it are playing with a fixed-pitch instrument that is not at 440, or historically-informed performance — neither of which is a first-year problem. If your tuner is showing everything as consistently sharp or flat, check the calibration setting before assuming the guitar is wrong.

When the tuner is right and the guitar still sounds wrong

Every string reads green, and the chords still sound sour. Two usual explanations.

Intonation. The guitar is in tune with itself at the open string but not further up the neck. Check it by comparing the twelfth-fret harmonic against the fretted twelfth-fret note on the same string — they should read the same. If the fretted note is sharp, the saddle needs moving back. That is a setup job; see does my guitar need a setup.

Fretting pressure. Pressing too hard bends the string sharp, especially near the nut on a guitar with high action. If chords sound sharp only when you play them and not when the tuner reads the open string, you are pushing too hard — or the action is too high and forcing you to. Guitar action too high covers how to tell.