OpenNetMeter is a simple and easy-to-use network traffic and data usage monitoring program for Windows, can tell you the total amount of transferred data that was received and sent to the PC as a whole, as well as data usage by each application. Compared to many of its peers, it's free, open-source and portable.

NetTraffic is a practical and easy-to-use free network traffic real-time monitoring software. It comes with tiny file size (less than 1 MB), few system resource usage, multi-language support, etc. It can monitor the network usage of computer in real time, and supports the display and analysis of traffic changes in both digital and graphical forms. In addition, it has a traffic statistics function, which can help users automatically record the total amount of traffics used over a period of time.