Size an internet connection on the people using it at once.
Offices run 30% to 50%. Hotels and student housing peak far lower than the bed count.
Browsing and email 2 Mbps. Video calls 4 Mbps. HD streaming 8 Mbps. 4K streaming 25 Mbps.
About 130 Mbps at peak, so a 200 Mbps link
Downstream capacity is rarely what people complain about. Upstream is: video calls, cloud backups and file sync all push, and asymmetric connections give the upstream a small fraction of the headline figure. Check the upload rating of any link before signing for it, and check whether the router can actually forward at the rated speed once firewall and inspection features are switched on.
What this cannot tell you
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Bandwidth per User Planner on RunTheTests — free browser-based sysadmin tools, no sign-up.