Decibly: Decibel Sound Meter

Pay once. No ads, no subscription. A real analog instrument: measure, run a session, keep the proof as PDF or CSV. Now with a threshold alert.

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 (dBA), 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 70 dBA) — 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.