Decibly: Decibel Sound Meter

Decibly turns your iPhone into a sound level meter that looks and feels like a real instrument: a large analog gauge with an amber needle, the live reading in crisp numerals, and color zones for quiet, moderate and loud.

MEASURE
• Live A-weighted decibel reading, updated 20 times a second
• Min, average (Leq) and max for the running session
• Scrolling chart of the last 60 seconds
• Reference points: 30 whisper · 60 conversation · 80 traffic · 100 danger

KEEP THE PROOF
• Start/Stop sessions with time, duration, min / avg / max and an optional note ("neighbors drilling", "night shift, hall 3")
• History with mini stats and a full chart for every session
• Export any session as a one-page PDF report or a CSV file

UNDERSTAND
• Exposure indicator with NIOSH-style guidance computed from the session average (e.g. about 8 h at 85 dB, about 15 min at 100 dB) — informational only
• Calibration slider (−15 … +15 dB) to match a reference meter

LIVE, EVERYWHERE
• Live Activity: the current level, zone color and elapsed time in the Dynamic Island and on the Lock Screen while a session runs
• Lock Screen "Measure" widget that starts a session with one tap; Home Screen widget with your last peak

NOISE ALARM & SCENES
• Set a threshold (default 85 dB) — every excursion gets a haptic pulse and is logged with time and peak
• Scenes: Baby room ≤ 40, Bedroom ≤ 35, Office ≤ 55, Street, Concert — one tap sets the alarm and gives a verdict such as "OK for sleep" or "Too loud"
• "Sounds like…" under the readout: whisper, quiet library, rain, conversation, vacuum cleaner, city traffic, lawn mower, motorcycle, concert, siren

EVIDENCE REPORT
• One-page Noise Report PDF with device model, iOS version, calibration, start/end, min / avg / max, the strip chart with alarm markers, every event and your note
• Shareable summary card image with the peak, date and note

PRIVATE BY DESIGN
• Audio is never recorded, stored or transmitted — the microphone signal becomes a number and is discarded instantly
• No accounts, no analytics, no ads, no location, no network
• Everything stays on your iPhone

PAY ONCE
• Every feature is included. No subscriptions, no in-app purchases, no "Pro" version.

Also: two alternate app icons, 8 languages, light and dark theme.

Decibly is not a certified measuring instrument; readings are approximate and depend on your device's microphone. The exposure indicator is general guidance, not medical advice.