Free Online Instrument Tuner

How to use this online tuner

1. Click “Start Tuning” and allow microphone access when your browser asks.
2. Play one note — pluck a single string or play a single key, close to your microphone.
3. Read the display. The big letter shows the nearest note. The cents meter below shows how far off you are: left = flat (tune up), right = sharp (tune down).
4. Adjust until it turns green. When you're within your chosen tolerance (±3 cents by default), the whole display turns green — you're in tune.

Why use DaTuner?

• Truly chromatic — detects all 12 notes in any octave automatically, so it works for any instrument: guitar, bass, ukulele, violin, cello, banjo, mandolin, piano, brass, woodwinds, even your voice.
• Alternate tunings built in — Drop D, Open G, DADGAD, half-step down and more. Select a tuning and the tuner targets the nearest string.
• Orchestra reference tuning — set A4 anywhere from 400–480 Hz for baroque pitch, A442 orchestras, or matching a fixed-pitch instrument.
• Note lock — tuning far below pitch? Lock the target note so the tuner guides you all the way, just like hardware tuners.
• Private by design — pitch detection runs entirely in your browser with the Web Audio API. No audio is recorded or uploaded.

Frequently asked questions