RPM Meter - Fan Tachometer

RPM Meter turns your phone into a simple sound-based tachometer. Point your phone at a spinning object and the app listens with the microphone, analyzes the sound frequency (FFT), and estimates the rotation speed in RPM (revolutions per minute) in real time.

What it does
• Real-time RPM reading from the rotation sound your phone hears
• Frequency detection with a live spectrum view so you can see the dominant tone
• Blades / poles correction: enter the number of fan blades or motor poles for a corrected reading
• Session statistics: current, maximum, and average RPM
• Hold to freeze the current value, and one-tap reset
• Clean, easy-to-read display with light and dark themes

Where it helps
• Fans and blowers: check the speed of a ceiling, desk, or PC fan
• Motors and tools: get a quick rotation-speed estimate for drills, pumps, and small motors
• DIY, makers, and hobbyists: a handy field check without a contact tachometer
• Learning: a hands-on way to understand frequency and rotation

How to use
1) Open the app and tap Start measuring
2) Hold your phone close to the rotating object, in a quiet place
3) If it spins with multiple blades or poles, set "Pulses per revolution"
4) Read the RPM value; tap Hold to freeze it or Reset to clear the statistics

Important
• This app needs microphone access to listen to the rotation sound. The microphone is used only for measurement — no audio is recorded, stored, or sent anywhere.
• Readings depend on the sound and are meant for general reference. Background noise, distance, and the type of rotating object affect accuracy, so values are best used as a guide, not a calibrated laboratory measurement.
• Works best with audible, steady rotation in a quiet environment.

Privacy
• Sound is analyzed only on your device in real time. No audio is uploaded or shared.

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