Guitar Tuner

About the Guitar Tuner

This free online guitar tuner listens through your microphone and tells you two things: which note you played, and how far off it is. The needle sits in the middle when the string is right. Left means the string is flat (too low) and needs tightening. Right means it is sharp (too high) and needs loosening.

It works for guitar, bass, ukulele and violin, and there is a chromatic mode that simply names whatever note it hears.

Your microphone is read only in your browser. No audio is recorded, stored or sent anywhere.

Tunings included

• Guitar — standard: E2 A2 D3 G3 B3 E4
• Guitar — drop D: D2 A2 D3 G3 B3 E4
• Guitar — half step down: E♭ A♭ D♭ G♭ B♭ E♭
• Guitar — open G: D2 G2 D3 G3 B3 D4
• Bass — 4 string: E1 A1 D2 G2
• Bass — 5 string: B0 E1 A1 D2 G2
• Ukulele: G4 C4 E4 A4
• Violin: G3 D4 A4 E5
• Chromatic: any note, no target

The string you are closest to lights up on its own, so you do not have to tell the tuner which one you are playing.

What "cents" means

A cent is one hundredth of a semitone. It is the unit tuners use because it is small enough to be useful:

• 0 cents — exactly in tune
• Within 5 cents — the tuner shows *In tune*; nobody will hear the difference
• 10 to 20 cents — noticeably out, chords start to sound muddy
• 50 cents — a quarter tone, halfway to the next note
• 100 cents — a full semitone; you are on the wrong note

Reference pitch

Standard concert pitch is A4 = 440 Hz, and that is the default. The slider lets you move it between 415 and 466 Hz for:

• A = 432 Hz — preferred by some players
• A = 415 Hz — baroque pitch, for period instruments
• Matching a piano that has drifted, so the whole band agrees

Features

• Real pitch detection through the microphone, not a play-along tone
• Needle plus a number in cents, so you can see exactly how close you are
• Eight tunings plus a chromatic mode
• Adjustable reference pitch from 415 to 466 Hz
• An input level meter so you can see the tuner is actually hearing you
• Works on a phone, so it fits in a gig bag
• No app, no sign-up, nothing recorded

Tips for a clean reading

• Play one string at a time and let it ring
• Pluck gently — a hard attack is sharp for the first moment, then settles
• Read the tuner about a second after you pluck, once the note has steadied
• Get away from fans, traffic and other players if the needle jumps around
• Tune up to the note, not down: come from below and stop at zero, so the string holds
• If a string will not stay in tune, stretch it and tune again

How to use it

• Choose your tuning from the list
• Press Start and allow the microphone when the browser asks
• Play one open string and let it ring
• Read the note name and the needle — left is flat, right is sharp
• Tighten for flat, loosen for sharp, until it says *In tune*
• Move to the next string and repeat
• Press Stop when you are done, to release the microphone