🎸 GUITAR TUNER
Tune your guitar in the browser.
Real-time pitch detection from your mic. Standard, Drop D, Open G, DADGAD, and Bass — switch tunings with one tap. Cents-off readout, string highlight, no app to install.
Tap the button to grant microphone access. Audio never leaves
your device — analysis runs locally in your browser.
—
Listening…
-50¢ flat
0
+50¢ sharp
—
How it works. The mic stream feeds an
AnalyserNode that hands us 4096-sample buffers ~50× per second.
Each buffer runs through a hand-rolled YIN
pitch-detection algorithm (cumulative mean normalized
difference + parabolic interpolation around the minimum).
The detected frequency converts to MIDI via
12·log₂(f/440)+69, then back to a note name and
cents-off-perfect. Green needle = within ±5 cents. Cyan = flat,
gold = sharp. The string-highlight grid swaps when you change
tuning, so the active string lights up regardless of whether
you're in Standard, Drop D, Open G, DADGAD, or Bass EADG.
Piano roll → scale detector
and BPM detector are the
companion tools.