Guitar Tuner Online — Free, Microphone-Based, No Download
This free online guitar tuner uses your device microphone to hear each string and tells you, in real time, whether it is flat or sharp. There is no app to download, no account, and nothing uploaded — it runs entirely in your browser on phone, tablet, or computer. Beyond standard tuning it supports Drop D, half step down, Open G, Open D, and DADGAD, plus an adjustable reference pitch including 432 Hz.
Pluck one string at a time and watch the dial: left of centre means flat, right means sharp, and the needle turns green when you are in tune. Open Settings to change the tuning or the reference pitch.
Ready to tune? Open the tuner, allow your microphone, and pluck a string.
Use the free Guitar Tuner →How to Use the Online Guitar Tuner
Because it works in any browser with your microphone, there is nothing to install. The flow is just three steps:
- Open the tuner — go to capsuletools.app/guitar-tuner/ and tap Enable Microphone. Allow access when your browser asks.
- Enable the microphone — tap Enable Microphone and allow access when your browser asks.
- Pluck a single string — play one string at a time, cleanly. The big letter shows the detected note and the dial shows how far off you are.
- Turn the peg until it's green — tighten to go sharp (right), loosen to go flat (left). When the needle centres and turns green, that string is in tune. Move to the next string.
It works as an acoustic guitar tuner online free no download or an electric tuner — anything your microphone can hear. For best results, tune in a quiet room and hold the guitar near the microphone. There is no sign-up and nothing to pay.
Supported Tunings
Open Settings (the gear) to pick a tuning. Each preset re-targets the six strings, and the string row highlights whichever one you are closest to as you play:
- Standard (EADGBE) — the default for most guitars.
- Drop D (DADGBE) — low E dropped to D for heavier riffs.
- Half Step Down (E♭) — every string down one semitone.
- Full Step Down (D) — every string down two semitones.
- Open G (DGDGBD) — strum the open strings for a G chord.
- Open D (DADF♯AD) — open strings ring a D chord.
- DADGAD — the modal Celtic/fingerstyle favourite.
How to Tune to Drop D Online
For Drop D tuning, choose Drop D in Settings. Strings five through one stay at standard pitch (A D G B E) and only the low sixth string drops from E down to D. Pluck the low string and loosen the peg until the dial centres on D2 and turns green. This guitar tuner online free Drop D mode is ideal for rock and metal, where a dropped low string makes one-finger power chords possible.
How to Tune a Guitar Half Step Down Online
Select Half Step Down in Settings to tune the whole guitar down one semitone: E♭ A♭ D♭ G♭ B♭ E♭. This is the online guitar tuner half step down microphone that many singers and bands use to relax string tension or fit a vocal range. Tune each string until its target centres — you do not need to learn the flat note names, because the tuner names the nearest note for you.
How to Tune to Open G and Open D Online
Open tunings let the open strings ring a full chord. Pick Open G (DGDGBD) or Open D (DADF♯AD) in Settings, then tune each string to its highlighted target. Open G is a slide and blues staple; Open D is common in folk and slide playing. The dial behaves exactly as in standard tuning — centre and green means in tune.
DADGAD Tuning — Online Guitar Tuner
DADGAD (D A D G A D, low to high) is a droning, suspended tuning loved in Celtic and fingerstyle music. It is rarely a built-in preset on hardware tuners, so a DADGAD tuner online free is the simplest way to reach it. Choose DADGAD in Settings and tune each string to its target; note that strings three and two move relative to standard tuning.
432 Hz Reference Pitch — What It Is and How to Use It
The reference pitch sets the frequency of the A above middle C. Standard concert pitch uses 440 Hz; some players prefer 432 Hz for a slightly warmer feel or to match other 432 Hz instruments. In Settings, lower the reference from 440 to 432 with the − button — every string target shifts to match, turning this into a 432 Hz guitar tuner online free. The reference is adjustable across the 430–450 Hz range, so you can match an orchestra, a piano, or a backing track precisely.
Frequently Asked Questions
Do online guitar tuners work?
Yes. A browser-based tuner uses the same microphone and pitch-detection math as a phone app, running in real time on your device. As long as you allow microphone access and you are in a reasonably quiet spot, it reads the pitch of each plucked string and shows whether it is flat or sharp, just like a hardware or app tuner. The accuracy is more than enough to get a guitar in tune by ear.
Is there a free guitar tuner online I can use without an app?
Yes — this is a free guitar tuner with no app to download, no account to create, and no sign up required. It runs entirely in your browser on phone, tablet, or computer. Just open the page, tap Enable Microphone, and tune. You can also add it to your home screen so it launches like an app and even works offline.
How do you tune a guitar down a half step online?
Open Settings in the tuner and choose Half Step Down (E flat). Every string target drops by one semitone — E flat, A flat, D flat, G flat, B flat, E flat from low to high. Then tune each string until the dial sits in the centre and turns green. The microphone hears the note and the tuner does the rest; you do not need to know the new note names.
What is 432 Hz guitar tuning and why do some players prefer it?
432 Hz refers to the reference pitch for the A above middle C. Standard concert pitch sets that A to 440 Hz; some players tune to 432 Hz because they find it warmer or want to match other 432 Hz instruments. In this tuner, open Settings and lower the reference pitch from 440 to 432 Hz — every string target shifts down to match, and you tune normally from there.
How do I tune my guitar to Drop D online?
Choose Drop D in Settings. This keeps strings 5 through 1 at standard pitch (A D G B E) and lowers only the low sixth string from E down to D. Pluck the low string and tune down until the dial centres on D2 and turns green. Drop D is popular for rock and metal because it lets you play power chords on the bottom strings with one finger.
What is DADGAD tuning?
DADGAD is an alternate tuning — D A D G A D from low to high — used widely in Celtic, folk, and fingerstyle playing. It gives a droning, open, suspended sound. Because it is rarely a built-in preset on hardware tuners, an online tuner with a DADGAD option is the easiest way to get there: select DADGAD in Settings and tune each string to its highlighted target.
Why isn't my guitar tuner picking up sound?
First, make sure you allowed microphone access — if you blocked it, the dial never moves. Then check you are in a quiet room, hold the guitar close to the microphone, and pluck a single string cleanly rather than strumming. Background noise, a muted microphone, or another app already using the microphone are the usual reasons a tuner stops responding. Reload the page and re-allow the microphone if it still does not react.
