Both Ookla and Comcast offer Web apps that allow people to test their Internet connection speeds. These apps measure both the download and upload speeds by transferring large files and testing how long it takes.
Because Internet speeds can vary over time, running tests multiple times and averaging the results can lead to a more realistic number. Ookla's test also lets users select a nearby server, and testing multiple servers can help average out any discrepancies cause by the testing server.
Tests typically deliver several pieces of information. The upload and download speeds show how fast the connection performed during the test. The ping result, which measures the latency of the connection, shows how quickly the tested computer was able to access the testing computer. While a low latency provides a faster initial connection, it doesn't guarantee a faster result overall. However, a low latency often means that the computer uses a more direct route, which can lead to better performance.
Internet service providers often advertise speeds up to a certain amount but don't guarantee minimum speeds. Users looking for the fastest speeds can look at information Ookla and other companies collect that measures the results of speed tests. Even if a particular provider advertises a lower maximum speed, it might have better performance than a competitor that advertises higher speeds.