Wi-Fi gets weaker with distance and walls. Test in the same room as the router, or use a LAN cable, for the most honest result.
Videos, app updates and cloud backups all share your bandwidth. Pause them before you press GO.
A VPN sends your data on a longer route and can lower your speed. Switch it off for a true reading of your line.
Internet plans use megabits per second. Divide by 8 to get megabytes per second. For example, 100 Mbps is about 12.5 MB/s.
Speed changes with network traffic. Run two or three tests at different times, like morning and night, and compare them.
Ping under 50 ms feels smooth for games and calls. High jitter can cause lag and choppy video even when your speed is high.