Guitar Tuner

A guitar tuner detects the pitch of each string and tells you whether it needs to be tightened or loosened to reach the correct note. Standard tuning for a six-string guitar is E2-A2-D3-G3-B3-E4, from the thickest to the thinnest string. Traditional hardware tuners require batteries and can be lost or forgotten, but a browser-based tuner works anywhere you have a device with a microphone. This online guitar tuner uses the Web Audio API built into modern browsers to capture sound from your microphone, analyze the frequency in real time, and display how close each string is to its target pitch. It supports standard tuning, drop D, open G, DADGAD, and several other popular alternate tunings. The entire process happens locally — your audio is never recorded, stored, or transmitted. The tuner works on desktop and mobile browsers, making it perfect for quick tune-ups before practice sessions, gigs, or recording.

When you grant microphone access, the Web Audio API captures your guitar audio as a stream of digital samples. The tuner applies a pitch detection algorithm — typically autocorrelation or the YIN algorithm — to identify the fundamental frequency of the sound. Autocorrelation works by comparing the audio signal with time-shifted copies of itself to find repeating patterns; the period of the strongest repetition corresponds to the fundamental pitch. The detected frequency (measured in Hertz) is then compared against the target frequency for each string. For example, the A string should be 110 Hz, and the high E string 329.63 Hz. The tuner displays the difference in cents — a logarithmic unit where 100 cents equals one semitone — so you can see precisely how sharp or flat your string is. A visual needle or meter shows real-time movement as you adjust tuning pegs. All audio processing happens in your browser using JavaScript and the native AudioContext, with zero server involvement.