Frequency Counter Hz Tuner

Content rating
Everyone
50+
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Content rating
Everyone
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About this app

Frequency Counter+ turns your iPhone into a precise audio analyzer with four purpose-built modes. Measure the dominant frequency of any sound, tune an instrument, read motor RPM by ear, or check the stability of your 50/60 Hz mains.

FOUR MODES
• Music — instrument tuner showing note name (A4, F#5) and cents off pitch (A4=440 Hz).
• Motor — RPM displayed first, with hints for 1500/1800/3000/3600 RPM standards.
• Hum — 50/60 Hz mains lock with deviation in ±0.01 Hz.
• Auto — Hz reading with closest musical note or mains harmonic shown live.

WHAT'S NEW
• Measurement History — every reading is auto-saved with a 7-day trend chart and insights like "+12% vs your 7-day average".
• Notes & Favorites — add a note ("fridge", "room 1") and star to any saved reading.
• Compare Mode — pick two saved measurements and view the difference side by side.
• Calibration Offset — fine-tune your microphone in ±0.1 Hz steps.
• Share Result — share your current frequency reading as an image.
• CSV Export — share all your measurements as CSV for spreadsheets.

CORE FEATURES
• Precise dominant frequency measurement (Hz)
• Large multimeter-style digital display
• Automatic 50/60 Hz mains hum detection with lock indicator
• Instant Hz-to-RPM conversion
• Waveform and amplitude visualization
• Microphone calibration

FOR MUSICIANS · AUDIO ENGINEERS · ELECTRICIANS · MECHANICS · HVAC TECHS · INDUSTRIAL DIAGNOSTICS

Available in 14 languages.
Updated on
May 18, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
This app may share these data types with third parties
App activity, App info and performance, and Device or other IDs
No data collected
Learn more about how developers declare collection
Data is encrypted in transit