Guitar Tuner

How to tune your guitar online

1. Click "Start Tuning."

   Allow microphone access when your browser asks.

2. Pluck a string.

   Leave Auto mode on and the closest tuning peg on the headstock highlights automatically, or tap a specific peg to lock onto that string.

3. Watch the meter.

   Turn the tuning peg slowly and watch the needle — left means flat (tighten), right means sharp (loosen).

4. Center the needle.

   The peg on the headstock turns green and the string is marked tuned once you're within a few cents.

5. Repeat for every string.

   Work through all 6 strings, then do a final pass since tuning one string can slightly pull the others.

How this tuner detects pitch

When you pluck a string, this tool analyzes the sound through your microphone using an autocorrelation algorithm — it compares the waveform against slightly delayed copies of itself to find the point where they line up most closely, and that lag reveals the exact frequency you're playing. This runs entirely in your browser via the Web Audio API; your microphone audio is never recorded, uploaded, or sent anywhere, and it disappears the instant you close the tab.

Standard guitar tuning

Standard tuning is the same across acoustic, classical, and electric guitars — only the tone differs, never the target pitches. From the thickest string to the thinnest:

How to tune by ear (the 5th fret method)

Worth knowing even if you always use a tuner — this is how guitarists tuned for decades before electronic tuners existed, and it's a genuinely useful skill for checking relative tuning quickly.

1. Tune the low E string first.

   Use this tool or any reference pitch to get the 6th string in tune.

2. Press the 5th fret of the low E string.

   Pluck it, then pluck the open A string — they should match.

3. Repeat for D, G, and high E.

   5th fret of each string should match the next open string up.

4. Use the 4th fret for the B string only.

   4th fret of the G string should match the open B string — this is the one exception.

Common alternate tunings

This tool includes Standard, Drop D, and Half Step Down directly. For anything else, our Chromatic Tuner listens for all 12 notes rather than a fixed set of strings, so you can tune each string to whatever note an alternate tuning calls for.

Getting a clean, accurate reading

Accurate tuning depends on a clean signal reaching your microphone. Play close to your device, reduce background noise, and pluck with a firm, steady attack rather than a light brush — a clean tone helps the tuner lock on faster and more reliably.

For acoustic and classical guitars, hold your device near the sound hole for the clearest signal. For electric guitars, tune unplugged or through a clean tone at low volume — distortion and heavy effects add extra harmonics that can confuse pitch detection. If a reading keeps jumping around, try muting the other strings with your picking-hand palm so only the string you're tuning is ringing.

Why the headstock, and why Auto mode matters

Laying the tuner out as a headstock isn't just decoration — it mirrors exactly what's in front of you when you're actually tuning, so there's no mental translation between "the tool says B string" and "which peg is that again." Each peg sits in the same relative position as it does on a real 3-a-side headstock, and turns green the moment that specific string reads in tune, giving you an at-a-glance record of which strings are done and which still need work.

Auto mode exists for speed: pluck any string and the tool figures out which one you meant based on the closest match among the current tuning's six targets, so you never have to stop and tap a peg first. Switch to "Tap a string" mode when a string is badly out of tune and might otherwise get matched to the wrong neighboring target, or whenever you just want to lock onto one specific string with certainty.

Guitar tuner vs. chromatic tuner

This tool is built specifically around the 6 guitar strings and a small set of common alternate tunings, which makes Auto mode fast and reliable — it only has to choose between a handful of known targets. Our Chromatic Tuner takes the opposite approach, listening for any of the 12 notes in the chromatic scale with no assumptions about which instrument or tuning you're using. Reach for this guitar tuner for everyday standard or Drop D tuning, and the chromatic tuner for anything more unusual — another instrument entirely, a deep alternate tuning, or simply tuning to a specific note by name.

More tools on ProDeviceTest

Practicing music rather than just tuning up? These run the same way — instant, no download, right in your browser.

• Alternate Tunings Guitar Tuner — 15 open and drop tunings on the same interactive headstock
• Bass Guitar Tuner — 4-string bass tuning with Standard and Drop D
• Guitalele Tuner — the guitar-ukulele hybrid, in A or E tuning
• Chromatic Tuner — tune any instrument to any of the 12 notes
• Metronome — practice with a steady, accurate beat
• Pitch Detector — see the note, Hz, and cents deviation of any sound
• All Instrument Tuners — the full category