4K streaming speed test
Broadband speed test for streaming
Updated 11 June 2026
Tools4K streaming speed test
Streaming 4K
Test for 4K streaming
~20 seconds · sustained download + jitter · pass/fail for 4K
Runs in your browser · no data leaves your device
4K Netflix, Prime, YouTube and iPlayer don't need a fast burst, they need a steady flow. We measure how much speed your line can hold over time, and whether it wobbles enough to drop you out of 4K mid-show.
4K streaming speed test
A streaming speed test is less about how fast your line is and more about how steadily it holds. Streaming is not where most broadband struggles, but a film that buffers at the worst possible moment is real, and the cause is rarely the speed you would guess. The test above checks both your download and how stable it stays. Here is how to read the result.
Far less than the adverts imply. A single 4K stream from Netflix or YouTube wants about 25 Mbps held steady and an HD stream about 5 Mbps, both per screen, so one 4K film does not trouble any modern line. The load word is "steady". Streaming hates a wobble more than a low average, because the apps buffer ahead and a connection that dips and recovers empties that buffer at the wrong moment, while a slower but rock-steady line plays clean. If your reading clears 25 Mbps for each 4K screen running at once, with a little headroom, streaming is not your problem.
Nine times out of ten the culprit is the wifi, not the line. The far end of the house, an ageing router or the crowded 2.4GHz band can all starve a 4K stream even when the line coming into the property is quick, because the speed dies on the way across the house rather than at the socket. The quick way to prove it is to run the test again wired, straight into the router. If it streams fine on a cable, the line is doing its job and the fix is your wifi, not a faster and more expensive package.
If the wired test is also short, or several 4K screens are fighting over one connection at the same time, the line is the limit and headroom is the answer. Add up every screen that streams at once, then leave room on top for the calls and downloads happening alongside. Headroom does not have to cost top-tier money: YouFibre and the other full-fibre builders sell serious speed at mid-tier prices where they reach, and the test above puts every line at your address side by side. Add up what speed you actually need screen by screen and you will buy the right tier rather than the biggest.