Guitar Tuner
Tune your guitar with your microphone and real-time note detection. 100% in your browser, nothing to install.
Pluck a string
Nothing is uploaded anywhere: the microphone is analyzed only in your browser.
Built by
Miguel Ángel Colorado Marin (MACM)
Built by
Miguel Ángel Colorado Marin (MACM)
Full-Stack Developer · Guadalajara, España
I develop web apps, digital tools and full projects — from design to deployment.
The guitar tuner listens through your device's microphone and detects in real time which note you're playing, comparing it against standard EADGBE tuning. Press "Start tuning", grant microphone permission, and pluck each string separately: you'll see the detected note, the exact frequency in Hertz, and how many cents you're off from the correct note (positive if too sharp, negative if too flat). The needle and color turn green when the string is in tune within a ±5 cents margin. Detection uses an autocorrelation algorithm, more reliable than simple frequency analysis for finding the fundamental note of a plucked string, even with harmonics involved.
Features
- ✓Standard EADGBE tuning
- ✓Note detection via autocorrelation
- ✓Real-time cents deviation
- ✓Needle-style visual indicator
- ✓100% in browser, no audio uploaded
How to tune a guitar?
- 1
Grant microphone permission
Your browser will ask when you press "Start tuning".
- 2
Pluck a string
Let it ring without muting it right away, in a quiet place if possible.
- 3
Watch the note and cents
The needle centers and turns green when you're in tune.
- 4
Adjust the tuning peg
Raise or lower the tension depending on whether the note is sharp or flat, and pluck the string again.
Frequently asked questions
Is my audio uploaded to a server?
No. The microphone is analyzed in real time with the Web Audio API directly in your browser, nothing is recorded or sent anywhere.
What are "cents"?
Each semitone is divided into 100 cents. A value of 0 means perfect tuning; positive means the note sounds sharper than it should, negative means flatter.
Does it only work for standard tuning?
The tuner detects any note you play, so it also works as a reference for other tunings, though the six reference strings shown are for standard EADGBE tuning.
Why isn't it detecting the note correctly?
Background noise can confuse detection. Try it in a quiet place and let the string ring clearly without muting it right away.
Related tools
Embed Guitar Tuner on your site
Add Guitar Tuner to any web page with a simple iframe. Free, with attribution to miguelacm.es.
<iframe
src="https://miguelacm.es/embed/guitar-tuner"
width="100%"
height="700"
frameborder="0"
title="Guitar Tuner — miguelacm.es"
></iframe>