Tuner + Metronome
Guitar Tuner and Metronome in One App
Two tools most players keep in two apps, built into one instrument — a ±1¢ chromatic tuner and a 40–240 BPM metronome, sharing the same LED display. Neither is behind the Pro unlock.
iPhone · iOS 17 or later · Apple Watch app requires watchOS 11
One Instrument
Why the Tuner and the Metronome Belong in the Same App
Tuning and keeping time are the two things you do before and during every practice session, and they are almost always split across two apps from two developers with two different ideas of what a button should look like. ChromTuner puts both on one LED display, and charges for neither.
The practical argument is switching cost. You tune, you start playing, you want a click, and you are now hunting through your home screen mid-warm-up. In ChromTuner the metronome is one thumb-swipe from the tuner, on the same screen you were already looking at, with the same readouts in the same places. Tune sits in the middle of three tabs and opens by default, so the tuner is still what you get when you launch the app cold.
The technical argument is audio. A tuner needs the microphone in measurement mode to see a raw, un-processed signal; a metronome needs playback mode to be audible at all. Those two configurations fight each other, which is why apps that bolt a metronome onto a tuner often produce a click that stutters or a readout that goes deaf. ChromTuner switches modes in exactly one place and lets only one tab make sound at a time, so neither tool degrades the other.
The click itself is scheduled on the audio clock rather than a repeating timer, which means it does not accumulate drift over a twenty-minute practice session the way a naive implementation does. Tempo runs 40–240 BPM with tap tempo, time signatures cover 2/4, 3/4, 4/4, 5/4, 6/8 and 7/8, and the downbeat is accented so odd meters are actually countable. All of it is free — the Pro unlock buys tuning breadth (17 presets, strobe and wave displays, temperaments, calibration), never the metronome and never detection accuracy.
Three Tabs
One Instrument, Three Tools.
Version 1.2 grew the app from a single tuner screen into a practice kit. Tune sits in the middle and opens by default — the other two are one thumb-swipe away, and only one ever makes sound at a time.
Metronome
40–240 BPM, tap tempo, 2/4 through 7/8. Free for everyone, on phone and wrist.
Tune
The chromatic tuner — now filling nearly two-thirds of the screen.
Strings
String-life tracking that counts the sessions you actually play.
In the Hand
Reads Like Hardware.
The warm LED look carries from your Mac to your pocket to your wrist — a tuner that feels like an instrument, wherever you play.
New in 1.2 · Apple Watch
Tune and Keep Time From Your Wrist.
The Apple Watch app runs the same YIN engine standalone, listening through the watch's own microphone — your phone can stay in your bag. The OLED display becomes the LED screen: a live meter, a string indicator that lights up as you move across the neck, and the big seven-segment note, readable at arm's length on a dark stage. Swipe across and 1.2's metronome is right there.
Metronome on Your Wrist. It clicks in time and taps the beat, so both hands stay on the instrument — and it keeps going with your wrist down.
Digital Crown. Turn it to flip through tunings on the tuner page, or to set the tempo on the metronome page.
Standalone & Offline. The engine runs entirely on the watch. No phone nearby, no network, no account.
Included free with the iPhone app · watchOS 11+
New in 1.2 · Metronome
Keep Time. Free for Everyone.
A metronome built into the same instrument, sharing the tuner's LED display — so the thing you practise with looks and reads like the thing you tune with. It isn't behind the Pro unlock, and it isn't a stripped-down teaser.
40–240 BPM. Dial the tempo or tap it in when you'd rather feel the number than pick it.
2/4 Through 7/8. Six time signatures with an accented downbeat, so odd meters actually read.
Sample-Accurate. Beats are scheduled on the audio clock rather than a timer, so the click doesn't drift.
Free on iPhone and Apple Watch · no ads, no account
New in 1.2 · Strings
Know When They're Due.
Every player guesses at this. ChromTuner tracks both how long a set has been on and how much you've actually played it — counting the sessions you tune — so the guitar that lives in its case and the one that gigs every weekend aren't treated the same.
Sessions, Not Just Days. A session only counts when you really tune: ten steady readings inside ±5 cents.
Pick It Up, It Follows. Choose an instrument and the tuner switches to its tuning automatically.
Down to the String. Record brand and gauge per set, and mark a single string when you replace just the one you broke.
One instrument free · Pro tracks your whole collection
Private by Design.
Audio is processed in memory, on-device, and never stored or transmitted. No analytics, no tracking, no account — the App Store privacy label reads "Data Not Collected" because there's nothing to collect.
Playing at a Desk? There's a Mac App.
ChromTuner for macOS reads any USB interface at full sample rate via Core Audio, lives in your menu bar, and is a one-time $6.99 purchase — direct from this site or on the Mac App Store.
See the Mac App →Free vs Pro
The Free Version Is a Tuner, Not a Demo.
Everything below the line ships free, at full detection accuracy — the Pro unlock buys breadth, never precision. Pro is a one-time $6.99 purchase, no subscription.
FAQ
Questions, Answered.
Quick answers about temperaments, instruments, accuracy, and what actually runs on your Mac.
Is the Metronome Free?
Entirely. The metronome is not part of the Pro unlock: 40–240 BPM, six time signatures from 2/4 to 7/8, tap tempo and an accented downbeat, on both iPhone and Apple Watch. Beats are scheduled on the audio clock rather than a repeating timer, so the click doesn't drift over a long practice session.Is the Free Version Actually Useful?
Yes. Free gets you chromatic mode (tune any instrument, any note), Standard E and Drop D guitar presets with tap-to-play reference tones, two displays, haptic in-tune feedback, the complete metronome, string tracking for one instrument, and the identical full-precision detection engine Pro uses. Nothing about accuracy is gated.What Does Pro Unlock on iPhone?
All 17 tunings, the Peterson-style strobe and waveform displays, string tracking for every instrument you own instead of one, 8 historical temperaments, A4 calibration from 349–500 Hz with auto-detect, capo through fret 11, ±11 semitone transpose, a live Hz readout, and full personalization. One purchase of $6.99 — no subscription, and Family Sharing applies.Is There an Apple Watch App?
Yes, included free with the iPhone app (watchOS 11 or later). It runs the same YIN detection engine standalone on the watch, listening through the watch's own microphone, so you can tune without taking your phone out — a live LED meter, a string indicator that lights up as you move across the neck, and the seven-segment note display. Swipe across for the metronome, which clicks and taps the beat and keeps running with your wrist down; the Digital Crown switches tunings on the tuner page and sets the tempo on the metronome page. Pro presets unlocked on your iPhone sync to the watch automatically.Does the iPhone App Work Offline?
Completely. The app makes zero network calls — audio never leaves your iPhone, and there's no account or analytics. The Apple Watch app runs its engine on the watch itself, so it works with your phone out of range too.How Accurate Is the Tuner?
Chromatic Tuner is accurate to ±0.14 cents on pure sine tones and ±1 cent in real-world use. The in-tune zone (green) opens at ±5 cents, which is what most studio engineers consider perfect intonation. Detection uses the YIN time-domain algorithm with a 4096-sample window, octave-error correction for plucked strings, and median-of-5 + exponential smoothing for stable readings at ~22 Hz.
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