Swisscom recommends the following applications for speed measurements:
Swisscom Home App: With the Swisscom Home app, you can measure the speed between your smartphone and Internet-Box as well as between the Internet-Box and Internet.
Internet-Box web portal: you can also measure the speed between the Internet-Box and the Internet in your Internet-Box web portal. To do this, enter 192.168.1.1 in the browser field or https://internetbox.home and perform a speed test. Please note that you only have access to the Web portal when your home network is connected to your Internet-Box.