Guitar tuner
Standard or drop D, string by string, with the sound kept on your device.
- Nothing is uploaded
- Works offline after first visit
- Open source
- No watermark · limit is your device’s memory; phones hold less
Tune your guitar online with the microphone: standard EADGBE or drop D, a needle for each string, and reference notes to tune by ear. It is free, and the sound from your microphone is not uploaded: everything runs in your browser on your device. Your browser asks for microphone permission, and after one visit and a short wait the page works offline.
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Play one string or note
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Done
Open the network tab. Your files never appear in it.
Add files and run the tool to see every request this tab makes.
Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.
Standard tuning, from the thickest string to the thinnest, is E2, A2, D3, G3, B3 and E4. A common way to remember it is “Eddie Ate Dynamite, Good Bye Eddie”. Press Start the tuner, play one open string, and the tuner lights the string it is closest to and shows how far off it is.
A worked example: you pluck the fifth string and the tuner shows A with the needle to the left and “18 cents flat: tune up”. Tighten that peg a little, pluck again, and stop when the needle sits in the shaded middle and the A button turns solid. On most guitars the pegs on the top side of the headstock tighten when turned away from you, so if the needle moves the wrong way, turn the other way.
Always tune up to a note. If a string is sharp, loosen it below the note first and then bring it back up: the gear then holds against the string’s pull, and the string stays in tune longer. New strings stretch for the first day or two, so expect to retune them several times.
For drop D, choose Guitar, drop D and bring the sixth string down a whole step, from E2 to D2, until the needle centres; the other five strings stay as they are. With no microphone, press each string button to hear its note and tune until your string and the tone sound as one.
How it works
- Keep Guitar, standard chosen, or pick drop D. Press Start the tuner and allow the microphone.
- Play one open string and let it ring. The nearest string lights up and the needle shows sharp or flat.
- Turn the peg until it says In tune, then do the next string, low E to high E.
In your browser, not on a server
Your browser opens the microphone (getUserMedia) with its noise suppression and automatic gain turned off, and the Web Audio API hands this page about 85 ms of sound twenty times a second. Each slice is compared with delayed copies of itself (the McLeod pitch method) to find the period of the note, which gives its frequency to a fraction of a hertz; the reading is then dropped. The string buttons play a tone from a Web Audio oscillator.
Compared with upload-based tools: Tuner apps ask for an install and access to much more than the microphone, and many tuner websites are buried in ads and trackers. Here the sound goes from your microphone to this tab and nowhere else, and nothing is kept.
Verify it yourself. Give the page a short while after one visit to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.
Questions
Does it work for acoustic and electric guitars?
Yes for acoustic, classical and electric through an amp or its speaker: the tuner listens through the microphone. An unplugged electric is quiet, so hold the phone or laptop close to the strings, or use a clip-on tuner.
Which way do I turn the peg?
Tightening raises the note and loosening lowers it. On a three-a-side headstock, turning the top pegs away from you and the bottom pegs toward you usually tightens, but guitars differ, so pluck while turning and watch which way the needle goes.
Why does my guitar sound out of tune even when every string is in tune?
Open strings can be perfect while fretted notes are off: that is intonation, set at the bridge saddles. Play the twelfth fret of each string; if the tuner shows it sharp or flat of the open note an octave up, the guitar needs a set-up.
Can I tune to half a step down (E flat)?
Choose Chromatic and tune each string down one semitone: E♭, A♭, D♭, G♭, B♭, E♭. The big letter shows the sharp name of each note, so look for D♯, G♯, C♯, F♯, A♯ and D♯.
Is the file uploaded anywhere?
No. There is no server in this process. The page is a static file and the work is done by code running inside your browser tab. Give the page a short while after one visit to save itself for offline use; then you can turn off Wi-Fi and it still works.
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Guides
- How to tune a guitarStandard tuning is E A D G B E, from the thickest string to the thinnest. Here is how to get each string there with a tuner, by ear, and what to do when it drifts.