Android itself also contain data usage app but its only display general information (only name of program and MB downloaded). If you not interested in more details of your data usage then this app is good for you but if you need more precise tools, I really suggest you to install GlassWire. It can track your mobile carrier data usage and Wi-Fi Internet activity and also monitor the real time data transmission by any application.
With its colorful graphs you can see the data usage in real time.Even their short study in surprising. It have ability to track data every time a new app accesses the network and begins using Wi-Fi or mobile cellular data or application runs in background.
Moreover, it not only analyze real time data usage but also you can view the data statistics of the day, week, month or even for year.
GlassWire’s data alerts can help keep you under your data limit.You just have to set the limit of your mobile data plan amd get alerted before you cross your carrier data limit to avoid over usage fees.
This app contains an additional security tool, if you see that unknown app constantly sending and receiving data from your device, then see its details and
delete the excess if this app not necessary.
The interesting about this app is, available for free on Play Store with no advertisement.This app works on devices running Android 4.4 or higher versions.