Sonometer

Sonometer turns your phone into a sound level meter that is quiet, precise, and completely private.

Point it at the world and read the room: a live dB(A) measurement, a running trace of how the sound around you rises and falls, and a plain-language sense of what that level actually means.

MEASURE
Live dB(A) readings with a continuous level trace, so you see the shape of the noise, not just a jumping number. Each reading is labelled in ordinary language, so 85 dB reads as what it is rather than an abstract figure.

SPECTRUM
A live octave-band analyser from 31 Hz to 16 kHz, drawn as a scrolling waterfall. See whether a room is dominated by low rumble, mid-range voices, or high hiss.

PATTERNS
Your day and your week as a single picture. Sonometer tracks LEQ (average level), your accumulated noise dose as a percentage, and how long you can safely stay at the current level. Compare today against your week and spot the hours that are doing the damage.

RECORD
Save a measurement session and keep it. Sessions store levels over time, not audio, and you can label them, revisit them, and export them as PDF or CSV when you need a record of what you measured.

CONCERT
A stripped-back, full-screen readout for loud rooms. Large enough to read at a glance in the dark, with a clear indication of when a level has become harmful and how much an earplug would give you back.

HOME SCREEN WIDGET
Keep the current level on your home screen while a measurement runs.

COMPLETELY OFFLINE, COMPLETELY PRIVATE
Sonometer has no internet permission. Not a limited one, not an optional one — the app has no ability to reach the network at all. Audio is analysed on your device in real time and is never uploaded, because it cannot be. There are no accounts, no analytics, no telemetry, no advertising identifiers, and no crash reporting.

Everything you save stays in local storage on your phone, can be deleted from inside the app at any time, and disappears entirely when you uninstall. Nothing is collected, and nothing is shared with anyone.

The microphone permission is used for one thing: measuring sound levels.

ABOUT ACCURACY
Your phone's microphone is not a calibrated Class 1 instrument, and no app can make it one. Phone mics compress loud sounds and vary between models, so treat Sonometer as an honest, well-behaved indicator rather than a legal or occupational measurement device. Within those limits, it is built to be as truthful as it can be — including about its own uncertainty.

Requires Android 8.0 or later. No network connection needed, at any point.