To test CenturyLink?s Internet speed, as of 2015, go to CenturyLink.com and choose the type of connection from the provided options. Click the Internet link located below My Account, scroll down to the bottom of the page, and click the Help link at the bottom right corner of the page.
On the Internet Help page, select Internet Speed, located on the left hand side of the screen, and then click the Speed Test link. Before beginning the speed test, close all open applications, including online videos, games and music players. Connect the computer directly to the modem and remove any switches, hubs or routers placed between the modem and the computer.
Because you cannot conduct the speed test on mobile devices, there is a separate application designed by Ookla for mobile users. Scroll down to the middle of the page, and click the Begin Test button located under Run The Speed Test. The speed test should take not more than 10 seconds to provide results.
If the speed is lower than expected, use the links at the bottom of the page to find out how to fix it. However, if the problem persists, contact the support team at CenturyLink for further assistance.