Free Online Guitar Tuner
Chromatic tuner with real-time pitch detection. Works for guitar, bass, ukulele, and any instrument you can point a mic at.
Tuner
How to Use This Tuner
- Click Start Tuner and allow microphone access when prompted.
- Play a note on your instrument. The detected note, frequency, and cents offset will appear.
- Center the indicator on the cents meter — when it turns green, you are in tune.
- Flat (red) means the note is too low — tighten the string. Sharp (amber) means too high — loosen it.
Standard Guitar Tuning Reference
Standard six-string tuning (low to high): E2 (82.4 Hz) · A2 (110 Hz) · D3 (146.8 Hz) · G3 (196 Hz) · B3 (246.9 Hz) · E4 (329.6 Hz). The guitar string row highlights the closest match so you know which string you are tuning.
Alternate Reference Pitches
Use the settings gear to switch between A=440 Hz (standard), A=432 Hz (often used in meditation and certain classical pieces), A=442 Hz (common in European orchestras), and A=443 Hz. You can also dial in any reference pitch from 400 to 480 Hz.
Frequently Asked Questions
Is this guitar tuner free?
Yes — completely free, no signup, no ads. It uses your browser microphone for pitch detection, and your audio never leaves your device.
What tunings does it support?
It's a chromatic tuner, so it works for any tuning. Presets included: Standard (A=440), A=432, A=442, A=443. You can also dial in any reference pitch.
Does it work for other instruments?
Yes — it detects any pitch your microphone picks up. Works for bass, ukulele, violin, voice, piano, brass, and anything else. The guitar string reference at the bottom is just a convenience for guitar players.
Does my audio get sent anywhere?
No. All pitch detection happens in your browser using the YIN algorithm. Your microphone input never leaves your device and no audio is recorded.
Why won't my microphone work?
Make sure you've granted microphone permission in your browser. On iOS Safari, you may need to tap the lock icon in the URL bar and enable Microphone. On laptops, check that no other app (like Zoom) is holding the mic.