Acoustic Tachometer

RPM from engine sound

Only for iPhone

Free · Designed for iPhone. Not verified for macOS.

iPhone

Estimate engine RPM from exhaust or engine sound using your iPhone microphone. Acoustic Tachometer estimates engine RPM from exhaust or engine sound using your iPhone microphone. Choose an engine profile, start listening, and watch the app lock onto the dominant firing frequency. The app reports RPM, confidence, harmonic support, and candidate frequencies so you can tune idle speed, compare engine behavior, and capture repeatable measurements without attaching hardware. Built for quick checks on cars, motorcycles, small engines, and rotary engines where a contact tachometer is inconvenient.

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Measure engine RPM with a redesigned instrument dashboard, a clearer live gauge, and a Garage for your machines and saved readings. New • Follow revs (beta): after a stable idle lock, follow rising engine speed on supported evenly firing engines. V8 and V-twin profiles remain limited to idle measurements. • Customize your app with six alternate icons, available with Pro. Improved • Read RPM trends more easily with labeled time and RPM axes, and see peak RPM while following revs. • Enjoy an updated layout with improved rotation on iPad. • Benefit from updated engine-sound analysis and signal evidence. Fixed • Choosing PDF report, CSV, or JSON backup now opens the share sheet immediately. PDF and CSV exports require Pro; JSON backup is free. • Deleting a saved reading now asks for confirmation.

The developer, Jan Sokol, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Seller
    Jan Sokol
    Size
    9.1 MB
    Category
    Utilities
    Compatibility
    Requires iOS 26.0 or later.
    • iPhone
      Requires iOS 26.0 or later.
    • Mac
      Requires macOS 26.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 26.0 or later.
    Languages
    English and 14 more
    • English, Czech, Dutch, French, German, Italian, Japanese, Korean, Polish, Portuguese, Russian, Simplified Chinese, Spanish, Traditional Chinese, Turkish
    Age Rating
    4+
    Copyright
    © 2026 Cognerva