Guitar tuner: tune guitar and ukulele
Allow the microphone, pluck a string, read the needle: the tuner detects the pitch right in your browser to about 1 cent. The sound is never sent or stored.
How it is calculated
Tune your guitar, ukulele or any other instrument with the microphone of your phone or laptop – no app, no sign-up. The pitch is measured in your browser and shown as a needle and in cents.
How to tune your guitar
- Choose the instrument: guitar (standard tuning E A D G B E), ukulele (G C E A) or chromatic for any note, e.g. violin, mandolin or voice.
- Click “Start tuner” and allow microphone access.
- Pluck a single string and let it ring. In Auto the tuner works out which string you mean; if a string is far out of tune, select it manually above.
- If the needle is on the left (flat), tighten the string; on the right (sharp), loosen it. Within ±5 cents the display turns green – the string is in tune.
- Tip: tune up to the note. If a string is sharp, loosen it well below the target first and then bring it up slowly – it stays in tune better.
Cents, concert pitch and note names
- Cents: a semitone has 100 cents. Most people cannot hear deviations below about 5 cents.
- Concert pitch: the standard is A4 = 440 Hz (ISO 16). Orchestras often tune to 442 or 443 Hz; some musicians use 432 Hz. Set the value and all target notes shift with it.
- The number after the note name is the octave: E2 is the low E string (82.41 Hz), E4 the high one (329.63 Hz), A4 the concert pitch.
Reference tone
The Reference tone button plays the target note of the selected (or last detected) string, so you can tune by ear – even without a microphone. The tone includes overtones so that low strings are audible even on small phone speakers.
How the detection works
The tuner compares the signal with time-shifted copies of itself (normalised autocorrelation after McLeod). The shift with the highest similarity is the period of the vibration; its inverse is the frequency. Because the measurement is averaged over many periods, accuracy with clean test tones between 82 and 1,000 Hz is better than 1 cent, and the overtones of a string do not cause octave errors.
Honest limits
Pluck one string at a time – the tuner cannot separate chords. Loud surroundings, hum or very quiet microphones make the reading jumpy; move closer to the instrument. Notes below about 60 Hz are not detected, so it is not suitable for the low strings of a bass guitar (E1 = 41.2 Hz). The accuracy refers to the measurement; strings, neck and intonation of your instrument decide how clean chords sound in the end.
Privacy
The sound is analysed only in your browser; nothing is recorded, uploaded or stored. “Microphone off” or leaving the page releases the microphone. Only the instrument and concert pitch are remembered (“Reset inputs” clears them).
To practise in time, use the metronome. If no sound arrives, try the mic test.
Frequently asked questions
How do I tune a guitar without a tuner?
With this online tuner you only need a phone or laptop with a microphone. Without a microphone, play the reference tone of each string and tune by ear until you no longer hear any beating.
What are the notes of standard guitar tuning?
From the lowest to the highest string: E2 (82.41 Hz), A2 (110 Hz), D3 (146.83 Hz), G3 (196 Hz), B3 (246.94 Hz), E4 (329.63 Hz) – remembered as “Eddie Ate Dynamite, Good Bye Eddie”.
How do you tune a ukulele?
Soprano, concert and tenor ukuleles are usually tuned G4 C4 E4 A4, counted from the string nearest your chin. The G string is higher than the C string (“re-entrant” tuning). Choose “Ukulele” in the tuner.
How accurate is this online tuner?
With clean test tones it measures to better than 1 cent between 82 and 1,000 Hz; a string counts as in tune within ±5 cents. In practice, background noise and the microphone limit accuracy more than the maths does.
Why does the needle jump around?
Usually several strings are ringing at once, or the room is noisy. Mute the other strings with your hand, pluck just one and hold the phone close to the sound hole or amp.
What do 440 Hz and 432 Hz mean?
That is the concert pitch A4 all other notes are based on. 440 Hz is the international standard. If you play along with a piano or orchestra tuned higher, set the concert pitch accordingly (e.g. 442 Hz).
Does the tuner work on my phone?
Yes, in current versions of Chrome, Safari, Firefox and Edge on Android and iPhone. The first time, the browser asks for the microphone; tap “Allow”.
Is my sound recorded or sent?
No. The pitch is calculated in your browser; nothing is recorded or transmitted. “Microphone off” releases the microphone immediately.
Sources and legal basis
- ISO 16:1975 – Acoustics: Standard tuning frequency (A4 = 440 Hz)
- MDN Web Docs – MediaDevices.getUserMedia()
- MDN Web Docs – AnalyserNode (Web Audio API)
- MDN Web Docs – BaseAudioContext.createPeriodicWave()
- W3C – Web Audio API
As of:
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