Frequency Counter+ Hz FFT

The number you read is the number that's there. Band labels now come from the analyser's own bins, and the tuner follows your A4 anywhere from 430 to 450 Hz.

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.