Guitar Tuner
Free online guitar tuner. It listens through your mic and shows which peg to turn and which way, right on a picture of the headstock. No install — plus ukulele, bass, Drop D and more.
Tighten a little at a time. Over-tightening can snap a string.
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Frequently Asked Questions
Do I need to install anything or sign up?
No. Open the page, press start, and allow the microphone. No app, no account, completely free.
Why does it need my microphone? Is anything recorded?
Reading the pitch of your strings requires mic input. The sound is only used for the calculation inside your browser — nothing is stored or sent anywhere. Press stop and the mic switches off immediately.
How does it know which peg to turn?
Pluck a string and its peg lights up on the headstock, with the direction and how far to turn shown below. Flat means tighten, sharp means loosen. Strings you have finished keep a check mark, so you can see what is left at a glance.
How accurate is it?
Within about ±1 cent. It measures the period of the waveform directly and interpolates between samples, which is far more precise than reading a frequency spectrum.
Can I tune a ukulele or a bass?
Yes. Pick ukulele (GCEA) or bass (EADG) from the tuning list and the string count and drawing change with it. For guitar there is standard (EADGBE) plus half-step down, Drop D, Open G and DADGAD.
It is not picking up my guitar.
Pluck one string at a time and keep the guitar close to the mic in a quiet room. Several strings ringing at once, or background noise, make the pitch impossible to pin down. Bluetooth earbud mics are low quality — a laptop or phone's built-in mic works better. When other strings ring along, the tuner filters out most wrong-string readings automatically. If a reading still looks off, tap the peg of the string you are tuning to watch only that string; tap again to release.
Can I change the reference pitch (A4)?
Yes, anywhere from 415 to 445 Hz. Useful when playing along with a piano that cannot be retuned, or with a wind ensemble at 442 Hz. Otherwise leave it at 440.
How to use
- 1Pick a tuning — Guitar standard is the default. Switch to ukulele, bass, Drop D and others from the list.
- 2Pluck one string — Press start, allow the microphone, then pluck one string at a time. That string's peg lights up on the drawing.
- 3Turn it as told — Tighten when it says tighten, loosen when it says loosen. Finished strings keep a check mark.
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