Why does my video keep buffering?
A speed test reports an average. Streams care about the slow seconds: one dip and the picture drops to a blur or pauses. This check records your speed every second for 30 seconds and shows the dips.
Streaming check
Downloads for 30 seconds and records the speed every second. On mobile data this uses data: at 100 Mbps, about 375 MB.
Dips only in some rooms? Try the Wi-Fi room check. Only when others are online? Smart Queue and scheduling big downloads help share the line.
How it works
The check downloads from Cloudflare for 30 seconds and records the speed every second. Streams buffer ahead, so what matters is the speed they can count on: the slowest seconds, not the average. The result is the speed held for 90% of the test, how many seconds fell below half the usual speed, and the best quality that steady speed supports.
Reading your result
- Steady enough for 4K
- At least 25 Mbps held steadily: several 4K streams can run at once.
- HD or SD
- At least 5 Mbps (HD) or 3 Mbps (SD) held steadily. Fine for one stream; more at once will drop quality.
- Dips
- Three or more seconds below half the usual speed. That's usually Wi-Fi interference or others using the line, and it's why video drops to a blur or pauses.
Questions
Why does Netflix buffer when my speed test is fast?
A speed test reports an average and hides the dips. Streams pause in the slow seconds, usually from Wi-Fi interference or someone uploading. Test in the room you watch in, and try the Wi-Fi room check.
How much speed does 4K streaming need?
About 25 Mbps held steadily for one stream, a little more for headroom. Steady matters more than peak: see how steady your line is with this check.