4 Apps to keep track of internet (Data) usage

My Data Manager - Monitors the amount of internet used in Android mobiles. This is fairly a new application with 1000,000 + downloads so far. Setup your data plan and billing cycle date while setting up this app. It can also be used to track WiFi usage and data consumption during roaming. This application provides the list of apps and amount of  data consumed by the same. Consumption of data is represented using different graphs like pie chart, bar graph and list. Representation of data is beautifully done and its interactive as well. However I experienced small lags while rotating the pie graph and switching between different types of graph. Usage of data will also displayed in notification tab through a small widget. Data used can be displayed either  in GB or in MB which is configured during the initial setup.

Users rating - 4.6

A&F rating - 4.2

Size - 1.5MB

Downloads - 1000,000+

Data Usage Defender - Every app has its own way to represent the data, this one does it in a sexier way than all other apps.  Consumption of data is shown in a meter with some flashy colors. This app keeps track of mobile data and WiFi usage. "Adjust" button at the top can be used to configure the plan and set the reminder. Mobile data can  be disabled automatically when usage of internet crosses a certain threshold. Apps and data used by  them are displayed in a simple list. For rooted phones , firewall can be set to block specific apps from using the internet. Internet speed test can also be performed using this application. This is a nice app to keep track of internet usage with some flashy UI.

Users rating - 4.3

A&F rating - 4.3

Size - 2.1MB

Downloads - 100,000+

3G Watchdog - This is the most simplest, most known and most downloaded app to keep track of internet usage. This is an ad supported version and you might notice some ads while exiting this app, however ads will not be displayed during roaming it seems. Real Time Traffic displays the number of received and sent bytes through a graph and also the respective app which is consuming that data.  Free version displays mobile data and WiFi usage but pro version has loads of features like 4G/3G usage, data usage prediction, rules to exclude and include data used in certain time period or upload/download or do not count 2G so on. If you are looking for a simple app to keep track of internet usage then this is the one for you.

Users rating - 4.7

A&F rating - 4.5

Size - varies with device

Downloads - 100,000,000+

Onavo Count - This app has the most pleasant and elegant interface among all four apps. Personally I liked the interface of this app and I will rate 5/5 for the same. This app has a unique feature which allows to compare your list of apps with apps which is consuming most amount of data in the world. Onavo Count uploads your usage also to cloud  to analyse the data along with other users data and generates the list of apps which consumes most amount of data in the world. And this list will be displayed to all users in App Guide section. Different notification like data usage cap, data usage threshold, app installation (this will let you know if newly installed app will fit your plan or not) and ongoing notification can be set.  Onavo Extend can be installed along with this to decrease the usage data without changing the way you are using your mobile. Network data to your mobile will be routed through Onavo servers which has compression and caching technology to reduce the amount of data consumed by your mobile. But only catch is every byte you download is tracked by Onavo servers. 

Users rating - 4.5

A&F rating - 4.7

Size - 3.5MB

Downloads - 1,000,000+

As per my knowledge, all apps picks the data usage information form OS, so I don't think we need to evaluate these apps on the basis of accuracy.  

All four apps displays the data usage in notification bar. Below is how it looks.