A clean, accurate tuner for guitar, bass, piano, ukulele, violin and more. Try it right here in your browser — no download, no signup, no nonsense.
Most tuner apps are bloated with paywalls, ads, and features you'll never use. iontuner does one thing well: tells you whether your instrument is in tune, accurately and instantly.
YIN-FFT autocorrelation, the same algorithm used in professional audio software. Locks onto the fundamental even through noisy environments and harmonic-rich plucks.
Four detection modes — Fast, Normal, Accurate, and Pro. Pro mode delivers sub-cent precision, designed for piano and reference tuning where every fraction matters.
Guitar, 12-string, bass, piano, ukulele, violin, viola, cello, mandolin, banjo, and chromatic. 40+ tunings built in — Drop D, DADGAD, Open G, Nick Drake's CGCFCE, and many more.
Modern standard, classical orchestral, or alternative tuning — choose your Concert A reference and every target frequency adjusts instantly. Persists across sessions.
Got an unusual tuning that isn't in the list? Create custom tunings with any number of strings. Save favorites, and your most-used tunings rise to the top automatically.
Tap any string to hear a clean reference tone at the target pitch. Tune by ear with confidence, or use it as a sanity check on your intonation.
Audio is processed entirely in your browser or on your device. Nothing is recorded, nothing is uploaded, nothing leaves the page. Works offline once loaded.
Free on the web, free on iOS. No paywalls, no ads, no “upgrade to remove” nonsense. Tuners shouldn't have a monthly fee.
Pick your instrument. Play a string. Match the needle. That's it. No tutorial, no onboarding flow, no email signup. The way it should be.
And quite a few things without. Vocal warm-ups, brass, woodwinds — switch to chromatic mode and any sustained pitch will be detected.
21 tunings — Drop D, DADGAD, Open G, more
Standard, Half Step Down, alt tunings
4-string, 5-string, 6-string, Drop D
Standard GCEA, Low G, Baritone DGBE
Standard GDAE, Cross AEAE
Standard CGDA
Standard CGDA
Standard GDAE
Open G, Standard, Open G 5-String
All 88 keys — sub-cent precision in Pro mode
Detects any musical note
Take iontuner everywhere — built natively for iPhone, iPad, and Android with the same principles. Sub-cent precision, 40+ tunings, custom tunings, reference tones, and 432 / 442 Hz support. Free, no ads, no subscriptions.