By measuring the download and upload rate these sites are able to accurately measure your current line throughput or internet connection speed. For most of these sites to work properly your require either Sun Java Plugin or Flash Plugin. So make sure you have them installed before you run the test.

• DSLReports Speed Test     –  Good Statistics
• Speakeasy Speed Test
• SpeedTest
• ThinkBroadband Speed Test
• Bandwidth Speed Test
• McAfee Internet Connection Speedometer – Very Good and Quite Reliable.
• CNET Bandwidth Meter Speed Test – Works only in US.

How these speed test works is by downloading files from their servers that will calculate our bandwidth speed from their Internet Services site. But take in mind that the bandwidth speed may be affected by the following factors:being located outside of the United States, performing other downloads and this test simultaneously, or executing programs that use your bandwidth to monitor other resources. Also note that some of these sites doesn’t have the services for testing for those outside of United States.