Free Online Guitar Tuner
Tune through your microphone, or play a reference tone and tune by ear. Over twenty tunings, from standard to eight-string drop E, plus your own. Nothing to install and nothing leaves your device.
Standard
Not listening
Strings
Everything happens in this browser. The microphone is only opened when you press the button above, nothing is recorded, and no audio is uploaded anywhere. Your tuning choices are saved on this device alone.
How to use this
- 1. Press Start and allow the microphone when your browser asks.
- 2. Play one string on its own and let it ring. The tuner will pick out which string it is.
- 3. Turn the machine head until the needle sits in the middle and the reading says in tune. Tighten if it says too low, slacken if it says too high.
- 4. Work through the strings, then go back round once. Tightening one string pulls the neck and nudges the others.
Press any string above to hear its pitch, then match it by ear. Listen for the wobble between the two sounds slowing down; when it disappears you are in tune.
In tune here means within 5 cents of the target, which is a good deal finer than most ears can hear on a single note.
How to tune a guitar properly
Tune upward, not downward
Always arrive at the note from below. If a string is sharp, slacken it well past the target and then bring it back up. Coming up to pitch takes the slack out of the winding and out of the machine head, so the string holds where you put it. Coming down leaves that slack in place, and the string quietly drifts flat again the first time you play it hard.
Go round twice
A set of strings pulls on the neck with something like fifty kilograms of tension between them. Tightening one string bends the neck a fraction and drops the others. One pass through six strings is never enough; a second pass will usually need only small corrections, and a third is rarely necessary.
Play one string at a time
Any tuner that listens through a microphone has to pick one pitch out of what it hears. Mute the strings you are not tuning with the side of your hand, play a clean note somewhere around normal playing strength, and let it ring rather than plucking repeatedly. A note that is struck too hard starts sharp and settles, which is why a tuner can look unsteady for the first moment after a hard pluck.
Check it at the twelfth fret
Once the open strings are right, play the harmonic at the twelfth fret and then the fretted note at the same place. They should read as the same pitch. If the fretted note is consistently sharp or flat against the harmonic, the tuning is not the problem: the intonation needs setting at the bridge, which is a job for a repairer or a patient afternoon.
A440, cents and why they matter
Modern tuning hangs off one agreed reference: the A above middle C sounds at 440 Hz. Every other note follows from it, each semitone a fixed ratio above the last, which is what lets a guitar, a piano and a clarinet play together at all. That system is called equal temperament, and it is a deliberate compromise: no interval except the octave is perfectly in tune, but every key sounds equally usable.
Cents exist because raw frequency is a poor way to talk about how far out something sounds. Ten hertz is an enormous error on a low E and a barely noticeable one two octaves up. A cent is a hundredth of a semitone, so the same number means the same musical distance wherever you are on the instrument. Most people start to hear a note as out of tune somewhere around five to ten cents against a sustained reference, and rather less than that when two notes are sounding together.
You will occasionally meet other references. Some European orchestras tune to 442 or 443 for a brighter sound; a historic organ or an early-music ensemble may sit near 415, a semitone below. That is what the calibration control in Setup is for. Unless you are playing with one of those, leave it at 440.
Alternate tunings worth trying
Drop D lowers the sixth string a tone. It costs nothing, takes ten seconds and gives you a low D plus one-finger power chords on the bottom three strings. It is the natural first step away from standard.
DADGAD is the one most people fall in love with. Strummed open it is neither major nor minor, which suits Celtic and folk playing enormously, and the ringing open strings make even simple shapes sound considered.
Open G and open D give you a full major chord across the open strings, which is why slide players live in them. Keith Richards famously took the lowest string off in open G entirely.
Lower tunings such as D standard, drop C and the seven- and eight-string sets need heavier strings to stay playable. Slacken a light gauge set that far and the strings rattle and read badly on any tuner, because there is not enough tension left to give a stable pitch.
Whichever you pick, tune to it in two passes like any other tuning, and expect the guitar to take a few minutes to settle after a large change in overall tension.
When to change them, and what to expect
Strings wear out long before they break. The signs are dullness, a set that will not hold its tuning through a single session, visible discolouration or flat spots where the frets are, and notes above the twelfth fret that read sharp on a tuner however carefully you set the open strings. Somebody practising most days is usually ready for a change every month or two; a guitar that comes out at weekends will go far longer.
A fresh set needs stretching. Fit them, bring them up to pitch, then pull each string gently away from the fretboard along its length and retune. Three or four rounds of that takes the worst of the creep out of them. Even then, expect to retune more often for the first day or two.
Change strings one at a time if you can. Taking all six off at once releases the whole tension on the neck at once, which is not harmful but does mean everything has to settle again afterwards.
Common questions
How do I tune a guitar with my phone or laptop?
Open the tuner, press Start and allow the microphone, then play one string at a time and let it ring. The tuner names the string and shows whether it is too low or too high. Turn the machine head until the needle settles in the middle, then move on to the next string and go round twice.
What is standard guitar tuning?
From the thickest string to the thinnest: E, A, D, G, B, E. At concert pitch those are 82.41, 110, 146.83, 196, 246.94 and 329.63 Hz. Nearly all guitar music assumes this tuning unless it says otherwise.
What does 'cents' mean on a tuner?
A cent is a hundredth of a semitone, so there are 1,200 of them in an octave. It is a way of describing how far off you are that works the same at any pitch. This tuner treats anything within five cents as in tune, which is finer than most people can hear on a single note.
Why does my guitar go out of tune so quickly?
New strings stretch for the first few days and need retuning often. After that, the usual causes are temperature and humidity changes, strings that have gone old and dull, or a nut that is pinching the string. A guitar that drifts badly within a single session is usually asking for new strings.
Do I need to tune differently with a capo on?
Yes, in the sense that the pitch each string sounds has changed. Set the capo fret in Setup and the tuner adjusts every target to match what the capped strings should now sound. Fit the capo just behind the fret and not too tightly, or it will pull the strings sharp.
Is this guitar tuner accurate enough for recording?
It resolves well below the five-cent window it calls in tune. For most playing and recording that is ample. What limits tuning accuracy in practice is rarely the tuner: it is intonation at the bridge, fret wear and how hard you press, all of which move the pitch more than a well-set-up tuner ever will.
Working on your timing as well? Our free online metronome has tempo and gap-click trainers built in.
Built for our own students, free for anyone to use.
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