Guitar Tuner
Free chromatic tuner with professional accuracy for guitar, bass, ukulele, and more.
Ready to Tune?
Click the button to enable your microphone. Make sure you're in a quiet environment.
Your microphone data is processed locally
Professional Tuning Features
Everything you need for perfect pitch and professional-quality tuning
Multiple Instruments
Tune guitar, bass (4 & 5 string), ukulele, and mandolin. Perfect for multi-instrumentalists.
Custom Tunings
Support for standard, alternate, and fully custom tunings. Configure each string individually.
Precision Tuning
Advanced frequency detection with visual feedback showing exactly how sharp or flat your strings are.
How to Use the Guitar Tuner
Whether you're a beginner learning your first chords or a professional musician preparing for a performance, our chromatic tuner provides the accuracy and flexibility you need.
How to Use
- Select instrument
Choose from guitar, bass, ukulele, or mandolin
- Choose tuning
Pick a preset or create custom tuning
- Start tuner
Click "Start Tuner" and allow microphone access
- Tune strings
Pluck each string and adjust until centered
Instruments
- Guitar
Standard, Drop D, DADGAD, Open G
- Bass
4-string & 5-string tunings
- Ukulele
Standard C, Baritone, Low G
- Mandolin
Standard GDAE tuning
Why Choose Acousterr's Guitar Tuner?
No Installation Required
Works directly in your browser
Chromatic Detection
Detects any note accurately
Visual Feedback
Clear meter with cent precision
Custom Tunings
For experimental musicians
Real-Time Frequency
Exact Hz measurements
String Tracking
Monitor tuning progress
Frequently Asked Questions
Accuracy, supported instruments, custom tunings, and what happens to your microphone audio.
- Is the Acousterr guitar tuner free?
- Yes — the tuner is completely free and needs no account. There is nothing to install and no sign-up step: open the page, allow microphone access, and start tuning.
- Which instruments can I tune?
- Guitar (6-, 7- and 8-string), bass (4- and 5-string), ukulele and mandolin. Each comes with its own tuning presets — Standard, Drop D, DADGAD, Open G and Half Step Down for guitar, Drop A and Drop E for the extended-range instruments, and Standard C, Baritone and Low G for ukulele.
- Can I use a custom or alternate tuning?
- Yes. Pick "Custom" and set each string to any note and octave you like, so a tuning that is not in the preset list is still one selection away. The tuner re-targets itself to whatever you configure.
- How accurate is it?
- Accurate enough to tune by, and it reads the note you played rather than the nearest harmonic. It uses the McLeod Pitch Method over a normalised autocorrelation, which locks onto the fundamental — the failure a naive tuner makes is calling a low E an octave high, and this is the technique that avoids it. Pitch is shown in cents so you can see how far off you are, not just which way.
- Does it work for a 5-string bass low B?
- Yes. The analysis window is sized from the lowest note the selected tuning expects, so a 5-string bass B0 at roughly 31 Hz gets a long enough sample to be measured — the case where fixed-window tuners fail. Switching instruments re-sizes it with no restart.
- Does my microphone audio leave my computer?
- No. Everything is analysed in your browser — the audio is never uploaded, recorded or sent anywhere, and the page makes no network request while the tuner is running. Your browser will ask for microphone permission because the tuner needs to listen, and you can revoke it at any time.
- Do I need a microphone, or can I plug my guitar in?
- Either works. The tuner listens to whatever your browser has as its audio input, so a laptop microphone is fine and an audio interface or USB guitar input works too — pick it as the input device in your operating system before starting.