Free Online Tuner
Online Tuner listens through your microphone and shows how many cents each note is off, on a needle or strobe display. Pick one of 24 tunings for guitar, bass, ukulele, violin, cello, mandolin or banjo, or use chromatic mode, and set A4 between 415 and 466 Hz. Click a string to hear its reference note.
- Presets:
- 24 tunings plus chromatic
- Reference:
- A4 from 415 to 466 Hz
- In tune:
- Within ±5 cents
- Price:
- Free
- Runs:
- Locally, in your browser
- Uploads:
- None: files never leave your device
- Account:
- Not needed
Quick answers
Is the sound recorded or sent anywhere?
No. The microphone signal is analysed live in your browser and is never recorded or uploaded.
Does it work on my phone?
Yes, in any recent mobile browser that allows microphone access. Hold the phone close to the instrument in a quiet room for the steadiest reading.
Processed on your device: your files are never uploaded. How it works
Network activity in this tab
What this page has requested since you opened the site in this tab. An upload is any request that sends data: POST, PUT, PATCH or a request with a body.
No uploads: nothing has been sent from this page.
No network requests yet.
To see every request, open your browser's developer tools (Network tab).
How to use the Online Tuner
- Choose your instrument and tuning, and change the A4 reference if your band tunes to 432 or 442 Hz.
- Press Start tuner and allow the microphone.
- Play one string at a time: the tuner finds the closest string and shows how many cents you are off.
- Tighten when it says tune up, loosen when it says tune down, until the needle sits in the green zone. Click a string to hear its reference note.
Credits & open source
Our own code plus open-source libraries. Thank you to the people who make these projects.
- PitchyPitch detection with the McLeod Pitch Method. © Ian Johnson · MIT
Web platform APIs used: Media Capture (getUserMedia), Web Audio API, Canvas 2D, localStorage.
Full license texts: third-party notices · all credits
Frequently asked questions
What is a cent?
A hundredth of a semitone. Within about 5 cents most people hear a note as in tune, which is why the green zone is ±5 cents.
What is the strobe view?
It imitates a strobe tuner: the bands drift left when the note is flat, right when it is sharp, and stand still when it is exactly in tune.