Decibel Sound Meter for iPhone · homasglobal443@gmail.com
Email homasglobal443@gmail.com and include your iPhone model and iOS version. We usually answer within two business days.
Decibly is not a certified measuring instrument. It estimates the A-weighted sound level (dBA; C-weighting is available in Settings) from your iPhone's built-in microphone, which was designed for voice rather than acoustic measurement. Readings are approximate and can differ from a professional sound level meter by several decibels, especially below ~35 dB and above ~100 dB, where phone microphones clip or bottom out. Typical values you should see: a quiet room 30–40 dB, normal conversation 60–70 dB, busy traffic around 80 dB. Treat the numbers as everyday reference, not as evidence for legal, medical or workplace-safety decisions.
Open Settings › Calibration. Place your iPhone next to a reference sound level meter in a steady noise (a fan or running water works well), compare the two readings and move the slider until Decibly matches. The offset (−15 to +15 dB) is applied to every reading and remembered. Tap Reset to return to the default. Remove any case that covers the microphone for best results.
No. The audio signal is analysed in memory to compute a level about 20 times per second and is discarded immediately. Nothing is written to disk or sent anywhere. Only decibel values (one per second during a session) are saved. See the Privacy Policy.
No. Decibly is a paid app bought once from the App Store, and every feature (unlimited sessions, history, PDF/CSV export, calibration, exposure indicator, alternate icons) is included. There are no in-app purchases or subscriptions, so there is nothing to restore. If you reinstall the app or set up a new iPhone with the same Apple ID, simply download it again from the App Store at no extra charge.
Set a threshold (default 70 dBA, or pick a scene such as Bedroom ≤ 35 dBA). During a session, every time the level rises above it Decibly plays a haptic pulse and logs an event with its time and peak. Events are marked on the strip chart and listed in the Noise Report. The alarm works only while the app is open — Decibly never uses background audio.
While a session runs, the current level, zone color and elapsed time are shown in the Dynamic Island and on the Lock Screen. The activity ends when you stop the session. You can add a "Measure" widget to the Lock Screen to start a session with one tap, and a small Home Screen widget shows the peak of your last session. Live Activities can be disabled per app in iOS Settings › Decibly.
The one-page PDF lists the device model and iOS version, calibration offset, session start and end, min / avg (Leq) / max, the level chart with alarm markers, every alarm event with its time and peak, your note and the accuracy disclaimer. There is also a 1080×1350 summary card image for messaging apps.
All three refer to the current or saved session. MIN is the quietest time-weighted reading, MAX the loudest peak, and AVG is the energy-averaged level (Leq), which is what noise guidance is usually based on. The gauge uses the "Fast" (125 ms) time weighting common on sound level meters.
It shows general public guidance based on NIOSH recommendations: 85 dB(A) for 8 hours, halving the time for every 3 dB increase (for example about 15 minutes at 100 dB). It is computed from the session average and is informational only. It is not a medical device or a personal dosimeter and does not replace professional advice.
Decibly measures in the foreground only. While a session is running, the screen is kept awake so you can leave the phone on a table. Switching apps or locking the phone pauses measurement; the session resumes when you return.
Open a session in History and tap PDF or CSV. The PDF is a one-page report with date, duration, min / avg / max and the level chart; the CSV contains one decibel value per second. Both open the standard iOS share sheet.
Check iOS Settings › Privacy & Security › Microphone and make sure Decibly is enabled. If another app is using the microphone (a call, a voice memo), finish it and tap Retry. Bluetooth headsets with a microphone can also take over the input; disconnect them to measure with the built-in microphone.
English, German, Spanish, French, Italian, Portuguese (Brazil), Korean and Ukrainian. The app follows your iOS language setting.
Swipe left on a session in History, or use Delete session on the session page. Deleting the app removes everything, because all data is stored on your device only.