Open Tuner for iPhone

Help with Open Tuner

Open Tuner is a tuner for 6-string and 12-string guitar, ukulele, banjo and bass. This version has no account, ads or subscription, and every instrument and tuning is included.

Tune a string

Pick your instrument from the tabs, then a tuning from the bar under them. Tap the peg for the string you want on the drawn headstock and pluck that string. The card shows the note Open Tuner hears, a meter and what to do: tighten, loosen, or in tune. Tuned strings get a check.

Why does it say "Pluck again"?

When the note it hears is far from the string you picked, or could be an octave off, Open Tuner won't tell you which way to turn. Tightening on a wrong reading is how strings snap. Pluck again closer to the phone, and check you picked the right peg.

Auto

Auto picks the string nearest the note you play. It's off at first, and even when it's on it never moves to the next string by itself.

Hear the note

Tap Play to hear the target note once. Hold Play for 2 seconds to repeat it until you tap Stop; tap a peg while it repeats to switch strings. The tuner doesn't listen while a note is playing.

12-string

Each pair is tuned one string at a time. The low four pairs have an octave string (shown in lower case); the top two pairs are the same note.

Reference pitch

Tap the i button to set A4 from 432 to 446 Hz. Most music uses 440 Hz.

Microphone

Open Tuner needs the microphone to hear your instrument. If you said no, turn it on in Settings ▸ Open Tuner; the Play notes work without it. Music or a podcast keeps playing while you tune; if it plays out loud, the tuner may hear it too, so headphones help.

Contact

Use support@openappco.com or Open AppCo support for questions. GitHub issues are public.

Updated October 14, 2026.