The tuner analyzes a short microphone sample in your browser with normalized autocorrelation, then converts the detected frequency to the nearest equal-tempered note relative to your selected A4 reference. The live audio is not recorded, stored, or uploaded.
Private browser utility / Social & Creator
Free Online Guitar Tuner
Runs entirely in your browser - no upload, no sign-up.
Ready to listen
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Detected note
-50-250+25+50
Frequency--
Cents--
Signal--
Open-string targets
6E2
5A2
4D3
3G3
2B3
1E4
Live audio is analyzed in memory only. Nothing is recorded or uploaded. Press Space to start or stop when focus is outside a control.
What is an online guitar tuner?
An online guitar tuner listens through your microphone, identifies the nearest musical note, and shows whether the string is flat or sharp. Start the mic, pluck one open string, and turn its tuning peg until the needle centers. This tuner supports standard tuning, Drop D, half-step down, and DADGAD without an app.
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How to use
- 01Choose a tuning
Select standard, Drop D, half-step down, or DADGAD and check the six open-string targets.
- 02Start the microphone
Press Start microphone and allow access when your browser asks. Use a quiet room and place the microphone near the guitar.
- 03Pluck one string
Let the string ring without touching the others. The tuner shows the detected note, frequency, and cents offset.
- 04Center the needle
Tune up when the reading is flat and tune down when it is sharp. A reading within 5 cents is shown as in tune.
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Who it's for
- Acoustic guitar players can tune through a laptop or phone microphone without extra hardware.
- Electric guitar players can place a device near an amplifier or use an audio interface selected by the browser.
- Alternate-tuning players can switch among Drop D, half-step down, and DADGAD targets.
- Teachers and beginners can see the exact note, frequency, and cents offset while learning what flat and sharp mean.
FAQ
Is microphone audio uploaded or recorded?
No. The tuner requests a live microphone stream and analyzes short sample windows in your browser memory. It does not create a recording or send the instrument audio to a server. Stop listening or close the page to release the microphone stream.
Is this online guitar tuner free?
Yes. You can use the tuner without an account, download, or session limit. Standard tuning, Drop D, half-step down, DADGAD, reference-pitch adjustment, the note readout, and the cents needle are all available on the page.
What limits affect microphone tuning?
Accuracy depends on your microphone, room noise, instrument volume, and how clearly one string rings. Browser processing works best for isolated guitar pitches from about 55 to 420 Hz. A clip-on or pedal tuner is a better choice on a loud stage.
What are the standard guitar tuning notes?
From the thickest, lowest string to the thinnest, standard guitar tuning is E2, A2, D3, G3, B3, and E4. At A4 = 440 Hz their approximate frequencies are 82.41, 110.00, 146.83, 196.00, 246.94, and 329.63 Hz.
What does cents mean on a guitar tuner?
A cent is one hundredth of a semitone. Zero cents means the detected pitch matches the nearest equal-tempered note. A negative value is flat and a positive value is sharp. This tuner marks readings from -5 through +5 cents as in tune.
Why does the tuner show the wrong string?
A guitar note contains a fundamental pitch plus louder overtones, and nearby strings can resonate. Mute the other strings, pluck one string near the 12th fret, move closer to the microphone, and wait briefly after the pick attack. Also confirm the selected tuning matches your target.
Can I use a reference pitch other than A4 = 440 Hz?
Yes. Set A4 from 432 to 446 Hz. The note and cents calculations follow that reference, which helps when tuning to an ensemble or recording that uses another concert pitch. Most modern music uses A4 = 440 Hz.