Guitar Tuner
Tune your guitar two ways: let the microphone read each string with a live needle and cents readout, or tune by ear with clean reference tones. Standard, Drop D, Half-step down, Open G and DADGAD — free, in your browser.
Tuning
Strings
Tap a string to hear its reference tone — no microphone needed.
Microphone tuner
Your microphone is analysed on your device only — nothing is uploaded, saved or recorded.
How the Guitar Tuner works
This online guitar tuner works two ways. Press Start microphone, pluck a string, and it detects the pitch on your device, showing the nearest note in big type with a needle that swings toward sharp or flat; centre the needle and the note turns green when you are within a few cents. Prefer to tune by ear? Tap any string button to play a clean reference tone and match it — no microphone required. Choose Standard, Drop D, Half-step down, Open G or DADGAD and the six target strings update for both methods. Everything runs client-side with the Web Audio API, so nothing is installed and, importantly, your microphone audio is never uploaded or recorded. Keeping time next? Try the Metronome, warm up on the Online Piano, or explore more Music Tools.
Open string frequencies
A guitar in standard tuning sounds these six open-string pitches. Every frequency below is equal temperament referenced to A4 = 440 Hz, which is exactly what the needle on this page targets.
| String | Note | Frequency | MIDI |
|---|---|---|---|
| 6th (low E) | E2 | 82.41 Hz | 40 |
| 5th | A2 | 110.00 Hz | 45 |
| 4th | D3 | 146.83 Hz | 50 |
| 3rd | G3 | 196.00 Hz | 55 |
| 2nd | B3 | 246.94 Hz | 59 |
| 1st (high E) | E4 | 329.63 Hz | 64 |
The low E string at 82.41 Hz is the lowest note on a standard 6-string guitar; the open high E is two octaves and a fifth above it.
Alternate tunings this tuner supports
| Tuning | Strings (as tuned) | Lowest pitch |
|---|---|---|
| Drop D | D2 A2 D3 G3 B3 E4 | 73.42 Hz |
| Half-step down | E♭2 A♭2 D♭3 G♭3 B♭3 E♭4 | 77.78 Hz |
| Open G | D2 G2 D3 G3 B3 D4 | 73.42 Hz |
| DADGAD | D2 A2 D3 G3 A3 D4 | 73.42 Hz |
Why does a string read one octave off?
A plucked guitar string produces a whole series of harmonics, not a single pitch, and on the wound lower strings the second harmonic can be louder than the fundamental. When that happens a detector can lock onto the octave above. Pluck a little more softly, nearer the neck than the bridge, and let the note settle for a moment before reading the needle. The low E string at 82.41 Hz is the most prone to this, because its fundamental is the quietest of the six.
Frequently Asked Questions
How do I tune my guitar with the microphone?
Pick a tuning (Standard is the default), press Start microphone and allow your browser to use the mic, then pluck one string at a time. The tuner finds the pitch, shows the nearest note in large type, and swings a needle left or right. Turn the tuning peg until the needle sits at the centre and the note turns green — that means you are within a few cents of being in tune. It highlights which string you are closest to, so you can work through all six.
Can I tune without a microphone?
Yes — you can tune a guitar by ear. Tap any string button to hear that exact pitch — for example the low E string at about 82 Hz — and match your string to the tone by ear. This needs no microphone and no permission, so it works on any device, and it is handy in noisy rooms where mic detection struggles.
Is my microphone audio uploaded or recorded?
No — the guitar tuner analyses the microphone stream live on your device with the Web Audio API and never uploads, saves or records it. Pitch detection runs entirely in the page, so no audio and no tuning data ever leaves your browser. Releasing the Stop button, or closing the tab, hands the microphone straight back to the operating system.
Which tunings does it support?
The guitar tuner supports Standard (E A D G B E), Drop D (D A D G B E), Half-step down (Eb Ab Db Gb Bb Eb), Open G (D G D G B D) and DADGAD (D A D G A D). Selecting a tuning shows its six target strings. Both the microphone needle and the reference tones follow that choice, so the same tool covers standard playing and alternate tunings.
Last updated: