Your provider promised “up to 150Mbps”, but Netflix keeps buffering and your video calls look like a slideshow. Before you start an argument with your broadband company, you need facts — and that means learning how to check broadband speed in the UK properly. Most people test it wrong, get a misleading number, and either panic unnecessarily or miss a genuine fault.

I’ve run hundreds of speed tests in homes across the UK, and the difference between a sloppy test and a proper one can be 100Mbps or more. Here’s how to get a number you can actually trust — and what to do with it.

How to Check Broadband Speed in the UK: The Right Way

Step 1: Test wired first

This is the step everyone skips, and it’s the most important one. Plug a laptop directly into your router with an ethernet cable and run the test from there. This measures the speed actually arriving at your home — your broadband line, which is what you’re paying for and what your provider is responsible for.

A test run over WiFi measures your home network, not your broadband. If the wired test shows 140Mbps and the WiFi test shows 35Mbps, your broadband is fine and your WiFi is the problem — calling your provider about it would be a waste of everyone’s time. (If WiFi is the issue, start with our guide on why WiFi keeps dropping.)

Step 2: Prepare properly

For an accurate result:

• Close everything else — pause cloud backups, stop streaming on other devices, close unnecessary browser tabs. Anything using the connection skews the result.
• Use a modern browser on a reasonably capable device. An eight-year-old laptop with a 100Mbps ethernet port physically cannot measure a 500Mbps connection — the hardware maxes out first.
• Test at different times of day. Run tests in the morning, afternoon and evening peak (7–10pm). Broadband that flies at 11am but crawls at 8pm is suffering from congestion — useful evidence.
• Run each test 2–3 times and take the middle reading. Single tests can be flukes.

Step 3: Use a good speed test

Not all speed tests are equal. The most reliable free options:

• Speedtest.net (Ookla) — the most widely used, with servers across the UK. Choose a nearby server manually for the most accurate result.
• SamKnows — Ofcom’s official measurement partner; their data feeds directly into Ofcom’s national broadband reports.
• Fast.com — Netflix’s test, simple and quick, good for checking streaming-relevant speeds.
• Your provider’s own test — worth running too, since it’s the number they’ll reference if you complain.

What Your Results Mean

Download speed

This is the headline number, and here’s what different speeds actually support:

• Under 10Mbps: Struggles with HD streaming on more than one device. Video calls may stutter. Below the UK’s “decent broadband” threshold.
• 10–30Mbps: Fine for a small household — HD streaming, browsing, video calls all work, but 4K is a stretch.
• 30–100Mbps: Comfortable for most families. Multiple 4K streams, gaming and home working simultaneously.
• 100Mbps+: More than most households need, but lovely to have — large downloads fly, and there’s headroom for everything at once.

Upload speed

The forgotten number. If your video calls freeze while everyone else looks fine, or cloud backups take forever, blame the upload. Standard fibre connections often deliver only 10–20Mbps up — and on older lines, much less. This is one of the biggest practical reasons to consider upgrading from fibre to full fibre broadband, which typically offers far better upload speeds.

Ping (latency)

Measured in milliseconds, ping is how quickly your connection responds. Under 20ms is excellent; 20–50ms is fine for most uses; consistently over 50ms suggests a problem. High ping ruins online gaming and can make video calls feel laggy even when download speeds look good.

What To Do If Your Speed Is Too Low

First, check what you’re actually promised

Your provider must give you a minimum guaranteed speed when you sign up — it’s in your contract. If your wired speed is consistently below that minimum, you have a clear-cut complaint. Ofcom’s guidance on broadband speeds sets out your rights, including the Broadband Speeds Code of Practice that most major providers follow.

The complaint process that works

1. Gather evidence: wired speed tests at different times over several days, with screenshots. Note the dates and times.
2. Report the fault to your provider with the evidence. Give them a chance to fix it — line faults, faulty routers and exchange problems are all fixable.
3. Know about automatic compensation: if a reported fault isn’t fixed promptly, most major providers owe you automatic compensation (£9.76/day for delayed repairs at current rates).
4. Escalate if needed: if the provider won’t resolve it, you can take the complaint to the relevant ombudsman (usually the Communications Ombudsman) for free.
5. Leave if you must: if speeds stay below the guaranteed minimum, you can typically exit your contract without penalty.

Check whether a better technology is available

Sometimes the honest answer is that your current connection type has hit its limits — a long copper line will never deliver 80Mbps no matter how much you complain. Check Ofcom’s coverage checker to see if full fibre has reached your street since you last looked. The rollout is moving fast, and many people are surprised to find their address was enabled in the last few months.

When the Broadband Is Fine But the WiFi Isn’t

This is the most common outcome of proper testing: the wired speed is great, but rooms far from the router are slow. That’s a home networking problem, not a broadband problem, and the fixes are straightforward — better router placement, or for larger homes, setting up a mesh WiFi system. Don’t pay for a faster broadband package hoping it’ll fix WiFi dead spots; it won’t.

Test properly, know your guaranteed minimum, and keep records. Armed with real numbers, you’re in a far stronger position — whether that means getting a fault fixed, claiming compensation, or confidently switching to a better deal.