PRTG Traffic Grapher is an easy to use Windows application for monitoring and classifying bandwidth usage. It provides system administrators with live readings and long-term usage trends for their network devices. PRTG is mainly used for bandwidth usage monitoring, but may also be used to monitor many other aspects of a network such as memory and CPU utilization. The user receives detailed and comprehensive bandwidth and network usage data.

NOTE: Free for personal and commercial use and limited to ten sensors. Other versions are available starting at $99.