Online Guitar Tuner
Press Start tuner, allow the microphone and pluck a string: the needle shows how many cents you are flat or sharp and turns green when the string is in tune. Choose from nine tunings or tap a string to hear its reference note.
Press Start tuner and allow the microphone, then play one string.
Tune in a quiet room, pluck one string at a time and let it ring. Everything runs in your browser — the microphone audio never leaves your device.
How to use the Online Guitar Tuner
- Pick a tuning such as Standard (E A D G B E) or Drop D. Leave A4 at 440 Hz unless your band tunes differently.
- Press Start tuner and allow microphone access when your browser asks.
- Pluck one string and let it ring. In Auto detect mode the tuner picks the closest string automatically.
- Turn the tuning peg until the needle is centred and the display turns green. Left of centre means flat (tune up), right means sharp (tune down).
- Need a reference? Tap a string button to hear its note, or switch to Manual string to tune one specific string.
Guitar string frequencies (A4 = 440 Hz)
These are the exact target pitches the tuner uses for standard tuning, from the thickest (6th) to the thinnest (1st) string. Each frequency is calculated with the equal-temperament formula f = 440 × 2(n − 69) / 12, where n is the MIDI note number.
| String | Note | Frequency | MIDI note |
|---|---|---|---|
| 6 (low E) | E2 | 82.41 Hz | 40 |
| 5 | A2 | 110.00 Hz | 45 |
| 4 | D3 | 146.83 Hz | 50 |
| 3 | G3 | 196.00 Hz | 55 |
| 2 | B3 | 246.94 Hz | 59 |
| 1 (high E) | E4 | 329.63 Hz | 64 |
Guitar music is written an octave higher than it sounds, so the low E string is notated as E3 on the staff but actually sounds at E2 (82.41 Hz).
Alternate tunings at a glance
| Tuning | Strings 6 → 1 | What changes from standard | Typical use |
|---|---|---|---|
| Drop D | D A D G B E | 6th string down a whole step | Rock and metal power chords, low D bass notes |
| Half-step down | E♭ A♭ D♭ G♭ B♭ E♭ | Every string down a semitone | Heavier sound, easier bends, matches singers' range |
| D standard | D G C F A D | Every string down a whole step | Doom, grunge and downtuned rock |
| Drop C | C G C F A D | D standard with the 6th string a further whole step down | Modern metal and hard rock |
| Open G | D G D G B D | Strings 6, 5 and 1 down a whole step | Slide guitar, blues, rock rhythm parts |
| Open D | D A D F♯ A D | Strings 6, 3, 2 and 1 lowered | Slide, folk and fingerstyle |
| Open E | E B E G♯ B E | Strings 5, 4 and 3 raised | Slide guitar (raises string tension) |
| DADGAD | D A D G A D | Strings 6, 2 and 1 down a whole step | Celtic, folk and ambient fingerstyle |
Raising strings above standard pitch, as in Open E, increases neck tension. If you play that tuning often, consider lighter strings or tuning to Open D and using a capo on the 2nd fret instead.
Tips for a stable, accurate tuning
- Tune in order and then check again. Changing one string slightly changes the tension on the neck, so go across all six strings twice.
- Pluck with medium force over the soundhole or neck pickup. A very hard attack makes the note go sharp for a moment before it settles.
- Read the sustained part of the note, not the first instant after plucking.
- New strings stretch. Gently pull each string away from the fretboard and re-tune until it stays in pitch.
- Check intonation: compare the open string with the note at the 12th fret. If the fretted note is sharp or flat, the saddle position needs adjusting.
Frequently asked questions
How do I tune my guitar with this online tuner?
Press Start tuner, allow the microphone, then pluck one open string at a time. The big letter shows which string the tuner thinks you are playing and the needle shows whether it is flat (left) or sharp (right). Turn the peg until the needle sits in the green zone in the middle.
Why does the tuner not react to my guitar?
Make sure the browser has permission to use the microphone, that the right input device is selected in your system settings and that you are close enough to the microphone. Pluck firmly and let the string ring; very quiet notes are ignored by the noise gate. Background noise, fans or other instruments can also stop a steady reading.
What does cents mean on a tuner?
A cent is one hundredth of a semitone. A string that reads −20 cents is a fifth of a semitone flat. Within about ±5 cents most listeners hear a note as in tune, which is why the gauge turns green in that range.
What is A4 calibration?
It sets the reference pitch for the note A above middle C. The modern standard is 440 Hz. Some orchestras use 442 or 443 Hz and some players prefer 432 Hz. All string targets move with the calibration, so everyone in a group should use the same value.
Should I tune up or down to the note?
Tune up to the note. If a string is sharp, loosen it until it is a little flat, then tighten it back up to pitch. Approaching from below takes up slack in the gear and the string holds its tuning better.
Does the tuner work for bass or 12-string guitar?
It is designed for six-string guitars. A 12-string can be tuned course by course: the octave strings of the lower four courses read as the same note an octave higher, so use Auto detect or a chromatic tuner for those. For bass guitar, a chromatic tuner works better.
Is my microphone audio recorded or uploaded?
No. The sound is analysed in real time inside your browser and is never stored or sent anywhere. Pressing Stop tuner releases the microphone.