iontuner

The honest tuner. Free, no ads, no subscriptions, no sign-up, no data collection.

iontuner does one thing well: it helps you tune your instrument quickly and accurately. Open the app, pick your instrument, play a string, watch the needle. That's it.

INSTRUMENTS
Built for guitar, 12-string guitar, bass, double bass, ukulele, violin, viola, cello, mandolin, banjo, piano, and chromatic mode. Tap "Show world instruments" to access oud, saz, charango, cuatro (Venezuelan and Puerto Rican), tres cubano, bouzouki (Greek and Irish), balalaika, erhu, and pipa — with proper regional tuning traditions for each.

40+ TUNINGS
Standard, Drop D, DADGAD, Open G, Half Step Down, and dozens more. Five double bass tunings including the historical Viennese tuning. Multiple regional traditions for oud (Arabic, Iraqi, Turkish, Egyptian) and bouzouki (tetrachordo, trichordo, Irish). Star your favorites for quick access.

FIVE CONCERT A PITCHES
440 Hz (Standard), 442 Hz (Orchestral), 432 Hz (Alternative), 430 Hz (Classical), and 415 Hz (Baroque). For period instrument musicians, modern orchestras, and everyone in between.

SUB-CENT PRECISION
Standard mode hits ±1 cent accuracy for everyday tuning. Pro mode goes sub-cent for piano tuning, double bass low octave, and reference work.

CUSTOM TUNINGS
Build your own tunings string by string. Save unlimited custom presets. Frequencies update automatically when you change Concert A.

REFERENCE TONES
Play a clean reference pitch for each string. Tap, tune by ear, tap to stop.

DESIGNED FOR YOUR INSTRUMENT
Each instrument has its own detection profile — buffer sizes, filter cutoffs, and harmonic correction tuned for what you're actually playing. Bowed strings get extra smoothing. Bass instruments get expanded low-frequency analysis. Double bass detection reaches down to B0 (30.9 Hz).

WHAT YOU WON'T FIND
No ads. No subscriptions. No in-app purchases. No "premium tier." No data collection. No analytics. No account creation. No paywall after seven free uses. No "unlock with rating." Nothing tracking you, ever.

10 LANGUAGES
English, Spanish, Portuguese, French, German, Italian, Russian, Arabic, Chinese (Simplified), Japanese, and Korean.

iPad AND iPHONE
Designed for both. iPad gets a sidebar layout that keeps everything visible.

PRIVACY
Audio is analyzed entirely on your device. Nothing leaves your phone. Ever.

Built by a solo developer who got tired of tuner apps full of ads and paywalls. iontuner is what a tuner app should be.

Open the app. Tune your instrument. Close the app. Make music.