Free online guitar tuner
Click the microphone in the tuner, allow access, and pluck a string. It hears the note and shows you how far off you are. Green means in tune.
Standard tuning is EADGBE, from the thickest string to the thinnest. For alternate tunings, tap Standard inside the tuner and pick the one you need.
How to tune your guitar
Pluck one string at a time, starting with the thick low E, somewhere quiet. The needle shows the pitch: left of centre means the string is flat, so tighten the peg. Right of centre means sharp, so loosen it.
Turn the pegs slowly. Small moves are enough, and overcorrecting is how strings snap.
Tune all six, then play a chord. If it still sounds off, run through the strings once more. New strings drift until they settle in.
How often should you tune?
Every time you pick the guitar up. Wood moves with temperature and humidity, and ten minutes of playing is enough to pull strings off pitch. A check takes thirty seconds, and everything you practise afterwards sounds better for it.
In tune? Now play something
The Daily Guitar Quest gives you a new routine every Monday for a year: 260 lessons, five skills a week, filmed from three angles so you can see both hands.