Buffering wheels, drops to 480p, and “loading” mid-episode all trace back to one of two things: your real download speed, or your WiFi. This page measures both ends of that.

How much speed per screen

One 4K stream needs about 25 Mbps; HD needs 5–8 Mbps. Add roughly 25 Mbps for every extra 4K TV running at the same time. Streaming is download-only, so upload and ping barely matter here.

Buffering at high speed is a WiFi problem

If the test reads fast but your show still stalls, the bottleneck is between your router and the TV — not your plan. Test next to the router, then in the room with the TV, and compare the two numbers.