Bandwidth

Internet Speed Needed for HD and 4K Streaming

The figures below are per simultaneous stream, and they are sustained rates rather than the peak number on a speed test. A line that peaks at 200 Mbps but dips under 10 during the evening will buffer; a steady 30 will not.

Steps last verified 22 August 2026.

What each quality needs

Quality	Sustained per stream	Comfortable line speed
SD	1–2 Mbps	5 Mbps
HD 720p	3–5 Mbps	10 Mbps
Full HD 1080p	5–8 Mbps	15 Mbps
4K (HEVC)	15–25 Mbps	35 Mbps

Multiply by the number of streams you run at once. A household watching two 1080p streams and one 4K stream wants roughly 40 Mbps of headroom before anything else on the network is considered.

Why the speed test says you are fine

A speed test measures a short burst to a nearby server under ideal conditions. Streaming is a long, steady pull from a specific host. The three things that break streaming while leaving speed tests looking healthy are:

Evening contention

Your local exchange saturates at peak time. Test at the moment it buffers, not the next morning.

Wi-Fi, not the line

The bottleneck is between the router and the device, which no speed test run on a phone next to the router will show.

Packet loss

Even 1% loss will stall a transport stream while barely moving the throughput figure.

How to test properly

Test from the device that buffers
Not from your phone, and not next to the router.
Test while it is buffering
The result five hours later tells you nothing about the moment it failed.
Run it three times
A single result can be an outlier. The lowest of three is the number that matters.
Compare wired and wireless
If Ethernet is stable and Wi-Fi is not, stop looking at your ISP.

Above roughly 25 Mbps sustained per stream, buying more speed changes nothing. Stability and the last few metres of your network matter far more than the headline figure.