Why new guitar strings won't stay in tune

Fresh strings keep going flat because they are still stretching and the windings are still settling. How to stretch them in five minutes, and what to check if the guitar still drifts.

October 24, 2026

New strings go flat for a simple reason: they are not finished stretching. The steel lengthens a little under tension, and the windings around the tuning post and the ball end at the bridge are still pulling tight. Every bit of slack that comes out of the system drops the pitch.

You can wait for that to happen over a few days of playing, or you can do it now.

Stretching new strings, in five minutes

1. Fit the strings and tune to pitch.
2. Take one string near the middle of the neck, around the twelfth fret, and pull it gently away from the fretboard, two or three centimetres. Move along the string and repeat at a few places.
3. Retune that string. It will have gone flat.
4. Repeat until pulling no longer moves the pitch much, usually three or four rounds.
5. Do the same for every string, then retune the whole guitar, since the neck has moved too.

A firm pull is enough. You are taking out slack, not testing the string, and a hard yank can break a string or lift a bridge pin.

Expect a small drift for the rest of the first day even after this. Nylon strings on a classical guitar stretch far more than steel, and take several days to settle however you treat them.

When stretching does not fix it

If a guitar still drifts after a careful stretch, something other than the strings is moving.

• Too few wraps on the post. Two to four wraps on a wound string, a few more on a plain one, wound downward so they stack neatly. One wrap can slip; a bundle of overlapping wraps can settle for days.
• A string catching in the nut. If tuning moves in sudden steps, or you hear a small ping as the string comes to pitch, it is binding in its slot. Pencil graphite in the slot usually fixes it; a slot that is too narrow needs a repair shop.
• A ball end not seated. On an acoustic, push each bridge pin down and pull up gently on the string to seat the ball end against the bridge plate before tuning.
• The guitar is moving. A floating tremolo, a neck reacting to a change in room temperature or humidity, or a change of string gauge will all shift tuning until the guitar settles. A different gauge often needs a setup.
• It is in tune open but not fretted. That is intonation, not tuning. The standard tuning guide shows how to test it at the twelfth fret.

Tune up into the note

However well strings are stretched, tune each one from below the target and bring it up to pitch. If you overshoot, go back below and come up again. A string that is let down to its note leaves slack around the post that works its way out as you play, and the string goes flat a minute later.