Sound Meter: Decibel dB Level

Turn your iPhone into a precise sound level meter. Sound Meter measures ambient noise in decibels (dB) using your device's built-in microphone — instantly see how loud your surroundings really are. Whether you're at a concert, monitoring workplace safety, or checking if toys are too loud, Sound Meter delivers real-time readings with a beautiful, intuitive interface. KEY FEATURES - Real-Time Decibel Gauge Instant SPL readings on a stunning animated gauge with color-coded safety zones. The needle responds smoothly as noise changes around you. - Live Sound Level Chart Track noise over time with a scrolling waveform chart. See exactly when spikes happen. The 85 dB danger line is always visible so you know when levels become unsafe. - Smart Noise Level Indicator Instantly know if your environment is Quiet, Moderate, Loud, Very Loud, or Dangerous — with real-world examples like "library" or "rock concert" for context. - Min / Average / Max Tracking Monitor minimum, average, and maximum dB readings throughout your session. Reset anytime to start fresh. - Professional Calibration Fine-tune accuracy with a manual offset slider. Compare against a reference SPL meter and adjust until values match for the best precision your device can deliver. - Hearing Safety Alerts Clear visual warnings the moment noise crosses 85 dB — the level where prolonged exposure causes permanent hearing damage. WHO IS THIS FOR? - Musicians & Concertgoers — Protect your hearing at rehearsals, gigs, and events. - Parents — Check if toys, speakers, or headphones are safe for children. - Workers — Assess workplace noise for occupational safety compliance. - City Dwellers — Document noise from traffic, construction, or neighbors. - Students — Learn about acoustics and sound physics with real measurements. - Anyone Curious — Find out exactly how loud everyday sounds really are. HOW IT WORKS Sound Meter uses Apple's AVAudioEngine with Measurement audio mode for the flattest microphone response. The app computes RMS amplitude from raw audio at 44.1 kHz and converts to decibels using standard SPL formulas. Results update 10 times per second. Note: Smartphone microphones are most accurate between 30–90 dB. Very quiet or extremely loud environments may show reduced accuracy. For lab-grade precision, use a calibrated external microphone. Download Sound Meter today and understand the sound world around you.