A free app for Android, by The Card Shop.
Sound Meter is a free, handy utility for measuring sound pressure levels and determining the noise level. It can be used to detect and measure noise and sound pressure levels in your environment.
It is a very useful tool for anyone who needs to stay on top of the sound environment, especially if you have a hearing loss or you simply want to know what is the noise level in your room or in the area where you are.
It is an app that is very easy to use and is compatible with most Android devices. It also has an extensive list of options that will help you in the process of measuring.