iperf is the gold standard for measuring throughput but it requires a shell on both ends. The default TCP mode is fairly intuitive and usually gives a good ide

iperf is the gold standard for measuring throughput but it requires a shell on both ends. The default TCP mode is fairly intuitive and usually gives a good idea of what is going on. For precise independent tests of up and down speeds you need to use UDP mode with increasing bit rates until you start to see significant packet loss in that direction. Repeat in the other direction. Another consideration is that the endpoint you are testing from (probably some cloud vm or server at work) will likely have different routing to your other endpoint (home) than other sites/services you visit. It is not unusual for eyeball ISP's to sometimes have congested peering with specific networks in specific locations while your work->home path will be clean.