Online tuner
Turn on the microphone and play a string: the needle shows whether the note is flat or sharp. Guitar, bass, ukulele, violin and many more, or every note in chromatic mode. Sound stays on your device.
“Auto” recognises the string you play. Click a string to make it the target and hear its note.
Offset over the last 10 seconds (cents)
How to tune a guitar or bass
- Pick the instrument and tuning, then click “Turn on the microphone” and allow access.
- Play an open string and let it ring. The detected note appears with its offset in cents.
- Needle to the left: the note is flat, tighten the string. Needle to the right: sharp, loosen it. It turns green when the string is in tune, and a ✓ appears on the string.
- Move on to the other strings, then go round once more: tightening one string slightly changes the others.
Frequently asked questions
What is concert pitch for?
Most music uses A = 440 Hz. Some orchestras tune to 442 or 443 Hz, baroque music to 415 Hz; change it to play along with a piano or recording that is not at A440.
What is a cent?
A hundredth of a semitone. An offset of 2 to 3 cents is inaudible to most ears; from about 10 cents you can hear it is out of tune.
The low string of my bass is not recognised
The low B of a 5-string bass (31 Hz) is hard to pick up with a phone or laptop microphone: play close to the mic, or tune that string with the 12th-fret harmonic, one octave higher. The reference tone can also play one octave higher.
Is the microphone sound recorded?
No: it is analysed live in your browser and is never recorded or sent.
See also: notes, scales and chords on the fretboard and the bass rhythm trainer.
Standard tunings
Scientific pitch notation (A4 = 440 Hz), with frequencies:
- Guitar (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).
- 4-string bass: E1 (41.2 Hz), A1 (55 Hz), D2 (73.4 Hz), G2 (98 Hz). A 5-string adds a low B (B0, 30.9 Hz).
- Ukulele: G4, C4, E4, A4, the G being higher than the C (“re-entrant” tuning).
- Violin: G3, D4, A4, E5, in fifths.
Common alternate tunings
- Drop D: the guitar's low string goes down a whole step to D. One-finger power chords, widely used in rock and metal.
- Half step down (E♭): every string a semitone lower, for a lower voice or a heavier sound.
- DADGAD and Open G (D G D G B D): open tunings for folk, slide and blues.
Pick the tuning from the list: the needle and target strings adapt.
Tips for stable tuning
- Always tune up to the note: if a string is sharp, slacken it below the note, then bring it up. The string locks better on the tuning post.
- New strings stretch for a few days: retune often, or gently stretch them by hand after fitting.
- Tune at playing temperature: an instrument brought in from a cold car drifts as it warms up.
- Check intonation at the 12th fret: if the fretted note is higher than the harmonic, the string is too short (move the saddle back); this is a luthier's intonation setup.
Playing with others
Agree on the same reference: a piano may be tuned to 442 Hz, a baroque ensemble to 415 Hz. Set the tool's reference pitch accordingly, or play the reference tone to tune by ear. To learn the notes once you're in tune, see the fretboard, scales and chords.
Guide written and checked by Erwan Hautot · updated 3 November 2026.