Decibel Meter & Noise Dose

Decibel Meter turns your phone into a real-time sound level meter. Measure ambient noise in decibels (dB), see live MIN/AVG/MAX, watch a waveform draw itself as the sound changes, and check whether the level is in a safe range.

What it measures
• Live dB sound level using the device microphone
• Current reading, MIN, AVG and MAX over the session
• Color-coded safety zones: under 70 dB green, 70–85 yellow, 85–100 orange, over 100 red
• Circular gauge with animated dial
• Live waveform chart over time

Reference table
A built-in reference shows what 15 common sound levels feel like: breathing at 10 dB, whisper at 20 dB, library at 30 dB, normal conversation at 60 dB, lawn mower at 85 dB, concert at 110 dB, airplane at 130 dB. Each entry is labelled safe, moderate, harmful or dangerous.

Calibration
Hold your phone near a calibrated reference (e.g. a professional sound level meter) and enter the reading. The app applies the offset so future measurements line up with the reference.

Noise dose (NIOSH)
For longer sessions the app computes the noise dose using the NIOSH standard: 85 dB criterion with 3 dB exchange rate. It reports TWA (time-weighted average), Leq (equivalent continuous level) and dose percentage, plus the maximum safe exposure time at the current level.

History and export
Save sessions on the device — start time, duration, MIN, AVG, MAX and the sample stream. Browse the last 100 sessions. Export any session as CSV (header + time/dB rows) and share via the system share sheet.

Threshold alerts
Set a custom dB threshold (default 100 dB). When ambient noise crosses it, the phone fires a haptic warning so you notice without staring at the screen.

Built for
Workers in loud environments, drummers and musicians, parents checking nursery noise, neighbours documenting disturbance, audio engineers spot-checking levels, anyone who wants to know how loud is loud.

Settings
• Update interval: 50 ms (fast), 100 ms (normal) or 200 ms (slow)
• Smoothing window: 3, 5 or 10 samples (moving average)
• Haptic feedback on/off
• Light/dark mode (follows system)
• 33 languages

Privacy
All measurements happen on your device. The microphone is used only while you're on the measurement screen. No recordings are uploaded. Works fully offline.

Disclaimer
Decibel Meter is an estimate only. Phone microphones vary by model and case. For occupational noise assessment, hearing-loss compensation claims, or any legally binding measurement, use certified Type 1 or Type 2 sound level meters.

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