Overview

Centerline is a chromatic tuner for musicians who want a clear readout without an account or an internet connection. Its strongest fit is guitarists who value on-device audio processing and a choice of pitch displays; the main caveat is that its frequency range excludes some low and high instruments.

Key features

Four ways to read pitch

Chromatic mode follows the nearest note from 62–800 Hz, including sharps and flats, and indicates whether the pitch is flat or sharp and where it settles. Simple, Trail, Strobe, and Workbench views let players choose how to read that information. Trail adds six seconds of pitch history, useful for seeing how a note moves rather than relying only on its current reading. The range covers many common tuning tasks, but not the full piano range or a bass guitar’s lowest notes.

Guitar workflow

Guitar mode offers automatic string detection or direct string selection, plus standard tuning, an All Strings progress view, and a headstock view. All Strings remembers individual readings as you work through the instrument, but it does not measure a chord at once. That makes it a string-by-string aid, not a substitute for simultaneous chord analysis.

Privacy and offline use

Pitch analysis happens on the device, and Centerline does not record, save, transmit, or share microphone audio. Tuning works offline, with no ads or Centerline account system. Usage analytics are optional and off until enabled; even then, they exclude audio and pitch data. The optional unlock is handled as a one-time store purchase, without the app receiving payment-card details or requiring an account.

Pricing

The free Chromatic plan costs 0.00 USD per free and includes 62–800 Hz chromatic tuning, all four display views, and Guitar mode with its six views. It is a substantial starting point for standard tuning, but omits the expanded tuning choices and calibration tools.

Centerline Complete costs 3.99 USD per once, billed as a one-time purchase. It adds Drop D, Half step down, D standard, DADGAD, and Open G, as well as custom six-string tunings, capo settings, A4 calibration from 432–446 Hz, and reference tones. Guitarists who need those options get a clear upgrade path without recurring charges; players content with the free tuning modes can stay on the free plan. There is no free trial and no recurring charge.

Platforms

Centerline is available on Android, iOS, and macOS. The App Store listing specifies iPhone and Mac availability, while the maker’s site links to Android and iPhone downloads. Offline operation is useful when tuning away from a dependable connection.

Who it's for

Centerline suits guitarists and other musicians who need a chromatic tuner with flexible displays, offline use, and explicit limits on microphone data handling. It is less suitable for players who need the lowest bass notes, the full piano range, or chord-wide measurement. Teams standardizing on other platforms should also look elsewhere: the supported platforms are Android, iOS, and macOS.

Pros and cons

Pro: On-device pitch analysis, no audio recording or sharing, and offline tuning make the privacy and connectivity tradeoffs clear.
Pro: Four chromatic views, including six seconds of pitch history in Trail, give players more than a single static readout.
Pro: The one-time Complete purchase adds alternate and custom tunings, capo settings, calibration, and reference tones without recurring billing.
Con: The 62–800 Hz range misses the lowest bass notes and parts of the piano range.
Con: All Strings tracks individual readings rather than measuring a chord at once.
Con: Expanded tunings and calibration require a paid unlock, and there is no trial.

Alternatives

Musical Tuner Apps is a useful place to compare more options. Choose ChromTuner if you want a free browser tuner with chromatic tuning, an LED meter, and browser microphone input, or need its iOS, macOS, and web availability. DaTuner is an Android alternative with a free, ad-supported plan and a trial; its Premium plan removes ads and adds features. Fender Tune offers a free Android and iOS tuner, with Tune Plus requiring a Fender account. Pano Tuner is another Android and iOS option, with an ad-supported free Android app and a 3.99 USD one-time iOS app. Bandmate Chromatic Tuner is free on Android, iOS, and the web, with no third-party ads. GuitarTuner.io is free across web, Android, iOS, macOS, and Windows, with no account or paid upgrade required for its web tuner. JustATuner is a free option for Linux, macOS, and Windows. n-Track Tuner offers Android and iOS versions, with a free version and a 2.99 USD one-time Pro version.

Verdict

Choose Centerline if you want offline, account-free tuning with on-device pitch analysis and a practical guitar workflow; the 3.99 USD one-time Complete unlock is sensible when its alternate tunings and calibration matter to your setup. Look elsewhere if your instrument falls outside 62–800 Hz, you need chord-wide measurement, or you need another platform.

	Centerline	Peterson Strobe
Free plan	Yes	No
Free trial	No	No
Paid from	Free	—
Open source	No	No
Platforms	Android, iOS, macOS	Android
Free plan	Yes	No
Strobe display	Yes	Yes
Alternate tunings	Yes	Yes
Custom reference pitch	Yes	Yes
Intonation monitoring	Yes	—
Offline mode	Yes	Yes
Available platforms	both	android

Centerline vs Peterson Strobe

Centerline

Peterson Strobe