PER STREAM
HD, full HD and 4K
One major streaming service recommends 3 Mbps for 720p, 5 Mbps for 1080p and 15 Mbps for 4K, for a stable connection.
Check a householdWHAT THE NUMBERS SAY
Add up
the streams.
Picture quality is partly a broadband question.
15 MBPS per 4K stream
10 Mbit/s 'Decent broadband' download speed
- Speed is per stream
- 4K needs about 3× 1080p
- Test more than once
- Sharper pictures, steadier streams
A 4K film needs about three times the connection speed of a 1080p one, and every screen in the house takes its own share. A little arithmetic tells you whether your line can keep up.
THE SHORT ANSWER
Speed per stream,
times the screens.
Recommended speeds are for one stream.
Households need to add them together.
THE HOUSEHOLD
Screens add up
Consumer Reports notes that the usual HD figure covers only one user at a time, and that many homes with several streamers need at least 50 Mbps.
See the numbers
THE CHECK
Test the line itself
Ofcom suggests running a free speed test, more than once, with a few different checkers, and using a network cable where you can.
How to testA QUICK HOUSEHOLD CHECK
What is everyone
watching tonight?
Pick a household evening to see the combined speed it needs, using one streaming service's recommendations. The bar shows how demanding it is.
Totals are simple sums of the per-stream speeds recommended in one streaming service's help centre: 3 Mbps (720p), 5 Mbps (1080p) and 15 Mbps (4K). Real use varies by service and network.
FOUR CHECKS FOR A STEADY PICTURE
Find the weak link
before you upgrade.
A slow stream is not always a slow line. Wi-Fi, busy devices and old equipment can all get in the way. These checks come from Ofcom's broadband and Wi-Fi tips.
Test more than once
Run a free speed test before changing anything, try a few checkers and test at different times, since speeds vary by day and time.
Pause the heavy users
Ofcom suggests checking whether others are downloading large files or streaming high-definition video while you test.
Restart and update
Reboot the router, any boosters or mesh units and the fibre box, and keep them switched on so they get automatic updates.
Move away from interference
Keep the router away from microwaves, baby monitors, cordless phones and speakers, which can interfere with the signal.
TWO NUMBERS WORTH KNOWING
The floor is low,
the ceiling is rising.
One figure on the UK's minimum broadband right,
one on how many homes can get gigabit speeds.
10 Mbit/s
'Decent broadband' download speed
Under the universal service obligation, homes and businesses can request a connection of at least 10 Mbit/s download and 1 Mbit/s upload if no affordable service is available. That is below one 4K stream's recommended speed.
MINIMUM · OFCOM
89%
UK homes that can get gigabit-capable broadband
Ofcom's spring 2026 update put gigabit-capable availability at 89% of UK homes (27.1 million), and full fibre at 82% (24.9 million).
GIGABIT · OFCOM 2026
Availability is not the same as take-up: Ofcom reported 12.4 million premises connected to full fibre, 47% of those that could get it.
MEGABITS, NOT MEGABYTES
Mind the
little b.
Broadband speeds are given in megabits per second (Mbps or Mbit/s): one megabit is one million bits. File sizes are usually in megabytes, and a byte is eight bits, so a 40 Mbps line moves about 5 megabytes a second at best.
Speed is about how fast data arrives each second, not how much you can use in a month. If your plan limits data, the streaming service's own advice is to lower the video quality setting.
Questions
Questions people ask
What broadband speed do I need for 4K?
One major streaming service recommends 15 Mbps or higher for a 4K (UHD) stream, 5 Mbps for 1080p and 3 Mbps for 720p. Each extra screen streaming at the same time needs its own share.
Is 10 Mbps enough for streaming?
For one or two HD streams, by those recommendations, yes. It is below the 15 Mbps suggested for a single 4K stream. 10 Mbit/s download is the UK's 'decent broadband' minimum under the universal service obligation.
Why does my stream buffer when my speed test is fine?
The test may have run while others were idle, or on a different device or room. Ofcom suggests checking for other heavy users, restarting equipment and moving the router away from interference.
What is the universal service obligation?
A right to request a broadband connection of at least 10 Mbit/s download and 1 Mbit/s upload for homes and businesses that cannot get an affordable service from existing networks.
Are Mbps and MB/s the same?
No. Mbps is megabits per second; MB/s is megabytes per second. A byte is eight bits, so 8 Mbps is about 1 MB/s.
Where the facts come from
Updated