Tune your instrument with your phone or laptop microphone. Play one string and the tuner shows the note, its frequency and how many cents it is sharp or flat, with a needle that turns green when you are in tune. Presets for guitar (standard and drop D), bass, ukulele, violin and cello pick the nearest string for you, and each string can play a reference tone.
loading toolHow to tune a guitar online
- Choose your instrument and press Start tuner.
- Play one string at a time and let it ring.
- Tighten if it says flat, loosen if it says sharp, until the needle is centred and green.
Good to know
- Tune up to the note: if you go too high, loosen below it and come back up so the string holds.
- A quiet room and the phone near the sound hole give the steadiest reading.
Questions
The browser says the microphone is blocked. What now?
Tap the 🔒 (or ⓘ) icon next to the web address, set Microphone to Allow and reload. On Windows and macOS also check the system privacy settings for the microphone.
What are cents?
A cent is one hundredth of a semitone. Within ±5 cents sounds in tune to almost everyone; the tuner marks it ✓ In tune.
Can I tune to 432 Hz or another pitch?
Yes. Change Reference A4 to the pitch your band or recording uses (most music uses 440 Hz).
Is my data private?
Yes. Everything happens inside your own browser: nothing you type or choose is uploaded to us or anyone else.
Is it free?
Completely free, with no sign-up, no watermark and no limit on how many times you use it. Light ads keep the site running.
