Frequency Counter+ Hz FFT
Tuner · RPM · 50/60Hz Meter
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
Now with Tuner · RPM · 50/60Hz modes, measurement history with chart, calibration, notes, favorites, compare and CSV export. Share results as image.
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.
Ratings & Reviews
Ads no longer interrupt you mid-task. Anything full-screen now waits until you have finished what you were doing, and the app stops showing a blank pause where an ad failed to load.
The developer, Kyu-Hee Jang, 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 Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Identifiers
- Usage Data
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Identifiers
- Usage Data
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Kyu-Hee Jang
- Size
- 71.4 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
18+
- 18+
- Contains
Advertising
- Copyright
- © Copyright 2026 Simon Jang. All rights reserved.