Online Guitar Tuner
Tune a guitar, bass, ukulele, violin or any instrument with your microphone. Accurate chromatic tuner with a cents needle, alternate tunings and A4 calibration.
Processed locally in your browser — nothing is uploaded.
Online Guitar Tuner
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— Hz
Press Start tuner and allow the microphone.
Strings
Auto: the tuner follows whichever string you play. Pick one to lock it.
Pluck one string at a time and let it ring. The needle shows how many cents (hundredths of a semitone) the note is off; within ±5¢ counts as in tune.
The microphone feed is analysed entirely in your browser — nothing is uploaded, streamed, or stored on a server. Stop releases the device immediately.
About Online Guitar Tuner
Press Start tuner, allow the microphone, and pluck a string. The tuner names the note you're playing, shows its exact frequency, and swings a needle left or right by how many cents (hundredths of a semitone) you are flat or sharp. Tighten the string when it says Too low — tune up, loosen it for Too high — tune down, and stop when the needle sits in the green band — within ±5 cents, closer than most ears can tell.
Pick your instrument and tuning, and the strings appear below with their target pitches. In Auto mode the tuner works out which string you're playing; click a string to lock onto it instead, which helps when a string is so far off that it reads as a different note. The speaker button beside each string plays a reference tone to tune by ear.
Instruments and tunings
- Guitar — standard E A D G B E, Drop D, half and full step down, Drop C, DADGAD, open G, open D and open E
- Bass — 4-string and 5-string standard, Drop D, half step down
- Ukulele — standard (re-entrant high G), low G, D tuning and baritone
- Violin family — violin, viola and cello
- Mandolin and 5-string banjo (open G and double C)
- Chromatic — names any note from about A0 to C8 for anything else: piano, wind instruments, voice
How it hears the note
The microphone signal is analysed in your browser with the YIN pitch-detection algorithm, which finds the waveform's repeating period rather than the loudest frequency. That matters on guitar: a plucked low E is often quieter at its fundamental than at its second harmonic, which fools simpler tuners into reading an octave high. The reading is smoothed with a short median filter so the needle stays readable as the note decays, and voice processing (noise suppression, echo cancellation and auto gain) is switched off because it is designed to remove exactly the steady tones a tuner needs.
Calibration
Standard concert pitch puts A4 at 440 Hz. Under Options you can set anything from 432 to 446 Hz — some orchestras tune to 442 or 443 Hz, and 432 Hz is a popular alternative — and every note and string target follows.
Example
Input
Guitar, standard tuning — pluck the low E string
Output
E2 · 81.6 Hz · -17¢ Too low — tune up
Target is 82.41 Hz. Tighten the string slowly until the needle centres and the note turns green, then re-check: tuning one string shifts the neck tension on the others.
Limitations
- Play one string at a time and let it ring — chords and several ringing strings confuse any single-note tuner.
- Laptop and phone microphones struggle with the lowest bass notes (B0 and E1); move the mic close to the instrument or the amp.
- A noisy room, a fan, or a heavily distorted amp channel makes the reading jumpy. Use a clean tone.
- Microphone access needs a secure (https) page and your permission. Nothing is recorded or uploaded.
Frequently asked questions
How do I tune my guitar with this online tuner?
Press Start tuner and allow the microphone, choose your instrument and tuning, then pluck one string. If the needle sits left of centre and it says tune up, tighten the string; if it's right of centre, loosen it. When the needle centres and turns green, move on to the next string, then go round once more.
What are the notes for standard guitar tuning?
From the thickest string to the thinnest: E2, A2, D3, G3, B3, E4 — 82.41, 110.00, 146.83, 196.00, 246.94 and 329.63 Hz at A4 = 440 Hz. A common mnemonic is Eddie Ate Dynamite, Good Bye Eddie.
Why does the tuner show the wrong note or jump around?
Usually because more than one string is ringing, the room is noisy, or the string is so far out that it really is closer to another note. Mute the other strings, pluck firmly but not hard, and if a string is way off, click it in the string list to lock the tuner to it.
What is a cent in tuning?
A cent is a hundredth of a semitone. Most people can't hear a difference of under about 5 cents on a single note, which is why the tuner treats ±5 cents as in tune. Being 50 cents off means you're halfway to the next note.
Should I tune to 440 Hz or 432 Hz?
Use 440 Hz unless you have a reason not to: it's the international standard, and recordings, pianos and other players almost always use it. Change the A4 setting under Options to match an orchestra (often 442 Hz), a piano that's tuned slightly off, or a 432 Hz recording.
Can I tune a bass or ukulele with it?
Yes. Pick Bass guitar for 4- and 5-string bass, or Ukulele for standard GCEA, low G, D tuning or baritone. For low bass strings, hold the phone or laptop close to the instrument — small microphones pick up little below 50 Hz.
Is my audio recorded or sent anywhere?
No. The microphone signal is analysed in your browser and discarded straight away — nothing is recorded, uploaded or stored. Stop releases the microphone immediately.
Why is the tuner not hearing anything?
Check the Input bar under the needle: if it doesn't move, the browser isn't getting sound. Make sure you allowed microphone access, choose the right input in the Microphone list, and check your system input volume. If another app such as Zoom is using the mic, close it and press Start again.