Online Guitar Tuner

Standard guitar tuning, from the thickest (lowest pitch) to the thinnest (highest pitch) string, is: E2 (82.41 Hz), A2 (110.00 Hz), D3 (146.83 Hz), G3 (196.00 Hz), B3 (246.94 Hz), E4 (329.63 Hz). This is based on the A4 = 440 Hz reference pitch. This tuning has been the standard since the mid-20th century and works for the vast majority of guitar music across all genres.

Our tuner uses advanced autocorrelation pitch detection algorithms to achieve accuracy within ±1 cent under optimal conditions. For comparison, most clip-on tuners have an accuracy of ±1 to ±3 cents, and even professional strobe tuners claim ±0.1 cent accuracy. For practical tuning purposes, getting within ±3 cents is considered perfectly acceptable — the human ear generally cannot distinguish pitch differences smaller than 5-6 cents.

1. Click the microphone button and allow browser microphone access when prompted.
2. Select the string you want to tune (or use "Auto" mode to let the tuner detect which string you're playing).
3. Hold your guitar close to your computer's microphone or device.
4. Pluck the string clearly and firmly with your finger or a pick.
5. Watch the gauge — if the pointer is left of center, the note is flat (tighten the string). If it's right of center, the note is sharp (loosen the string).
6. Adjust the tuning peg until the pointer stays in the green zone (±5 cents).

A cent is a logarithmic unit of measure for musical intervals. One semitone (the distance between two adjacent frets on a guitar) equals 100 cents. One cent is 1/100th of a semitone. On a guitar, being off by just a few cents can make chords sound slightly dissonant. The green zone on our tuner represents ±5 cents, which is well within the range of acceptable tuning for most ears. For reference, the difference between A4=440 Hz and A4=441 Hz is approximately 4 cents.

Several factors can cause a guitar to go out of tune: new strings need time to stretch and settle; temperature and humidity changes cause wood to expand or contract; old or worn strings lose their elasticity; loose tuning pegs may slip; aggressive bending or heavy strumming can detune strings; and nut or bridge issues can cause binding. Always stretch new strings gently after installation and tune up to pitch (rather than down) for better stability.

Yes — modern browsers require HTTPS (or localhost during development) to access the microphone via getUserMedia. If you're seeing a permission error, make sure you're accessing this page over a secure HTTPS connection. This is a browser security requirement, not a limitation of our tuner. All major browsers (Chrome, Firefox, Safari, Edge) enforce this policy.

Absolutely! This tuner is fully responsive and works on iOS and Android devices. Simply open this page in your mobile browser, grant microphone permission, and you're ready to tune. For best results on mobile, hold your phone within 1-2 feet of your guitar's sound hole and minimize background noise. The built-in microphones on modern smartphones are surprisingly capable for tuning purposes.

Popular alternative tunings include: Drop D (DADGBE — lower the 6th string to D), Open G (DGDGBD — great for slide guitar and blues), Open D (DADF#AD), DADGAD (popular in Celtic and folk music), Half-Step Down (Eb Ab Db Gb Bb Eb — used by many rock bands), and Open E (EBEG#BE). While our tuner focuses on standard tuning, you can still use it for alternate tunings by selecting the target note manually using the frequency display.