Piano Tuner Pro - Multi-String

Piano Tuner turns your iPhone into a precise, fast, and genuinely usable tuning tool — built around how pianos actually work, not just generic chromatic tuning.
Most pianos have more than one string per note: two in the middle register, three across the treble. If those strings drift apart, even by a few cents, the note loses its bloom and starts to beat. Piano Tuner is built for exactly this. Switch between 1-, 2-, and 3-string modes and watch each string land on pitch independently, so your unisons ring clean.
REAL-TIME PITCH DETECTION
A responsive autocorrelation engine listens through your mic and locks onto the fundamental in milliseconds. The note name and octave appear instantly, with live frequency in hertz right below.
A DIAL YOU CAN READ AT A GLANCE
A smooth, weighted needle sweeps across a −50 to +50 cent arc. The whole readout shifts color as you close in: amber when you’re off, red when you’re sharp, and a clean teal the moment you’re within a few cents of perfect. No squinting at tiny numbers mid-tune.
CENTS OR HERTZ, YOUR CALL
Tap once to switch the readout between cents and hertz. Work in cents for fine unison matching, or hertz when you want the raw frequency. The dial and per-string panel follow whichever you choose.
PER-STRING UNISON PANEL
Set the app to 2 or 3 strings and each one gets its own live deviation bar. Bring the first string to pitch, then match the rest to it by eye — no mutes, no guesswork, no beating.
CLEAN, FOCUSED, DARK
A calm dark interface with a single bright “in-tune” cue keeps your attention on the one thing that matters: the pitch. Subtle haptics confirm every tap. Portrait-locked and distraction-free.
WHO IT’S FOR
• Piano owners keeping their instrument in shape between professional visits
• Students and teachers checking pitch by ear and by number
• Technicians and hobbyists who want a fast reference in their pocket
• Anyone tuning a multi-string acoustic instrument
No accounts. No clutter. Just open it and tune.
Note: Piano Tuner uses your device microphone to detect pitch. It works best in a quiet room.