Why is your broadband so slow?
Slow broadband almost always comes down to one of three things: congestion at busy times, weak WiFi inside your home, or a line that just can’t deliver the speed you’re paying for. Work out which one you’ve got first, because the fix for each is completely different.
Broadband is a shared service. In the evening, when half the street is streaming, gaming and on video calls at once, the network has far more to carry, so speeds can dip. Ofcom’s own measurements have found speeds tend to be slowest around 9pm and quickest overnight, with full fibre lines holding up best when everyone piles on together.
It’s not always the connection itself, though. Often the real culprit is your WiFi: thick walls, a router shoved in a cupboard, or a dozen devices fighting over the same signal. From the sofa it feels exactly like slow broadband, but the cause is inside your home, and the fix is nothing like sorting out a fault on the line.
How can you tell if your broadband is actually slow?
Plug a laptop straight into your router with a cable and run a speed test, once at a quiet time of day and again at around 9pm. If the wired result is poor both times, you’ve got genuinely slow broadband rather than a kit problem. If the cable speed is fine but WiFi feels sluggish, the trouble is in your home, not on the line.
Run the test a few times and jot down the result, the date and the time. You’ll want that record if you end up complaining, and it lets you hold what you’re actually getting up against what you were promised. Our guide to running a broadband speed test walks through the tools and what the numbers mean.
What is your minimum guaranteed speed?
Your minimum guaranteed speed is the slowest speed your provider says your line should ever reach, and it’s the figure you can actually hold them to. The big number in the advert is an average that not everyone gets. The guaranteed speed is personal to your address.
You’ll find it on the Key Facts document or contract summary you got when you signed up. It usually sits well below the headline figure, so a deal advertised at around 36Mbps might carry a guarantee closer to 25Mbps for your line. If your real speed keeps dropping under that guarantee, you have a genuine case to take to your provider about the slow broadband. For more on what drags a connection down, we have a separate explainer on what affects your internet speed.
Can you leave your contract because of slow broadband?
Yes. If your speed falls below the minimum guaranteed figure and your provider can’t fix it, you usually have the right to walk away without paying an exit fee. That protection comes from Ofcom’s Broadband Speeds Code of Practice, which most of the big providers have signed up to. Here’s how the process runs:
| Step | What happens |
|---|---|
| 1. Test and log | Wired speed tests, dated, at quiet and peak times |
| 2. Report it | Tell your provider your speed is below the guaranteed minimum |
| 3. The fix window | They get 30 days to bring you back above the guarantee |
| 4. Your right to exit | If they can’t, you leave penalty free, including bundled phone and TV |
Providers signed up to the code, checked July 2026, include BT, EE, Sky, TalkTalk, Plusnet, NOW Broadband, Virgin Media, Utility Warehouse and Zen Internet. You can read the full detail on Ofcom’s right to exit guidance.
Quick checks before you complain
- Test your speed over a cable, not WiFi, to rule out an in home problem.
- Run the test at a quiet time and again at peak, around 9pm.
- Dig out your minimum guaranteed speed from your Key Facts document.
- Keep a dated log of your speed test results.
- Report the fault and give your provider their 30 days to fix it.
How to fix slow broadband or switch to something faster
If the trouble is your WiFi, a handful of free tweaks often make a real difference. Move the router out into the open, away from thick walls and big metal objects, instead of tucking it behind the telly. Restart it now and then, keep it upright, and use any quality of service setting to put video calls and gaming ahead of background downloads.
If the line itself can’t keep up, especially on older copper or cable connections during the evening rush, the lasting answer is usually a faster, more modern connection. Full fibre runs all the way to your home and tends to hold its speed far better when the whole neighbourhood is online, and it’s spreading fast: Ofcom counted 12.3 million full fibre lines in the UK by mid 2026, up 38% in a year. If your current deal is coming to an end, or you’ve won a penalty free exit over slow broadband, it’s a good moment to see what else is available at your address.
Switching is more straightforward than it used to be. A quick comparison shows the speeds and prices on offer where you live, so fixing slow broadband doesn’t have to mean guesswork.
Frequently asked questions about slow broadband
- How slow does my broadband have to be before I can complain?
- There’s no single national figure. The benchmark is your minimum guaranteed speed, which is personal to your line and listed on your Key Facts document. If you regularly fall below it, you have grounds to complain.
- Will switching to full fibre stop my broadband slowing down at night?
- It usually helps. Full fibre tends to hold its speed better through the evening peak than older copper or cable lines, though no connection is completely immune to busy time dips.
- Does bad weather affect broadband speed?
- It can on older copper lines, where damp and faults creep in over time. Full fibre is far less affected. If your speed drops sharply whenever the weather turns, it’s worth reporting to your provider.
- Is my slow connection a WiFi problem or a broadband problem?
- Test with a laptop plugged into the router by cable. If the wired speed is fine, your WiFi is the weak link. If it’s still slow over a cable, the problem is your broadband.
- Can I get money back for slow broadband?
- Sometimes. If your provider can’t meet your guaranteed speed, you can usually ask to move to a cheaper package instead of leaving, or leave penalty free. Any refund depends on your provider and the terms of your contract.
