A free app for Android, by Coolexp.

Sound Meter is a free app to measure the sound level in the environment around you. It is a handy tool for everyone to use in daily life and in the workplace. At the same time, it is a useful tool for professionals to measure and monitor the level of noise in the environment.

It is very easy to use. Just open the app, select the microphone from the list, and start measuring. The results will be displayed on the screen and on the graph. You can save your results and review them later.

The application has a built-in noise reference table that allows you to find out whether the noise level is harmful to your health.