Frequency Counter: Hz Meter

Content rating
Everyone
1K+
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Content rating
Everyone
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About this app

Frequency Counter is the most accurate audio frequency meter, Hz counter, and instrument tuner for Android. Measure the dominant sound frequency in real time with your phone's microphone — no extra hardware needed.

Turn your Android phone into a four-in-one frequency lab: read any tone in hertz, tune instruments, count RPM, and verify 50/60 Hz mains hum.

▶ MAIN FEATURES
• Frequency meter — dominant frequency in Hz, live from the microphone
• Instrument tuner — tune guitar, piano, violin and more with cents precision
• RPM counter — measure rotation speed from sound or vibration
• 50/60 Hz mains mode — check power-line and electrical hum frequency
• Real-time FFT with high-resolution peak detection (20 Hz–20 kHz)
• Adjustable averaging, smoothing and sensitivity
• Hold mode to freeze the reading
• Dark mode, works fully offline, no account needed

▶ HOW TO USE
1. Open Frequency Counter and allow microphone access
2. Pick a mode: frequency, tuner, RPM or 50/60 Hz mains
3. Point the phone at the sound source
4. Read the live frequency in hertz, the musical note, or the RPM

▶ WHO USES FREQUENCY COUNTER
• Musicians and instrument makers tuning by exact frequency
• Audio and AV engineers checking tones and signal pitch
• Electricians and technicians verifying 50/60 Hz mains
• Mechanics and makers measuring motor and fan RPM
• Piano tuners needing cents-accurate pitch
• Students learning acoustics, sound and signal processing
• DIY hobbyists testing speakers, buzzers and alarms

Microphone permission required. External USB microphones supported.
Updated on
Jul 7, 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

What’s new

Thanks for using our app! This update brings behind-the-scenes performance and stability improvements for a smoother, more reliable experience. Your support means the world to us.