Slow broadband: is it your wifi or your line?

Slow broadband is hardly ever one problem. It is two, and they have almost nothing to do with each other. Either the connection arriving at your house is underperforming, or the connection is fine and your home is losing most of it between the router and the sofa. Every useful thing you can do next, including the one that lets you walk out of your contract, depends on working out which of those two you have. It takes about ten minutes.

Slow broadband is two problems, not one

Think of it as a pipe and a sprinkler. The pipe is the line into your property, which your provider owns and is responsible for. The sprinkler is everything after the router: walls, distance, the number of devices, the age of the box on the shelf. Your provider is responsible for the pipe. You are mostly responsible for the sprinkler, and no amount of complaining will change that.

Most people who ring up about speed are describing a sprinkler problem in pipe language. That is why the call so often ends with nothing happening.

Is it your wifi or your line?

Run one speed test with a computer plugged into the router with an ethernet cable, and one on your phone standing in the room where it usually feels worst. If the wired result is close to what you pay for and the wireless one is a fraction of it, your line is fine and your wifi is the problem. If the wired result is also poor, the line is the problem and it belongs to your provider.

That single comparison settles more arguments than anything else in this guide. It is also exactly how a provider will look at it when you complain, so you may as well do it in the same order they will.

How should you test your broadband speed?

Use a device connected to the router by a cable, because wifi slows the signal down and hides what the line is really doing. That is Ofcom's own advice, not a technicality invented by providers to make complaints harder.

Then test properly rather than once. Pause anything downloading, run the test a few times across different days, and make sure some of those runs land between about eight and ten in the evening, when the network is busiest. Write the results down with the date and time. A screenshot of one dismal Tuesday is an anecdote. A fortnight of evening tests is evidence.

What your provider actually promised

Not the number on the advert. Providers signed up to Ofcom's voluntary codes of practice on broadband speeds have to give you a minimum guaranteed download speed before you buy, without you having to ask for it, alongside an estimate based on your own address rather than a national average.

The word voluntary is doing real work in that sentence. The codes bind the providers that signed them, and not everyone selling you a connection has. It is worth checking before you sign rather than after something goes wrong, and it is one of the questions we think is fair to ask any network, large or small.

Go and find your minimum guaranteed speed now, in the order confirmation or the contract summary you were sent. If your wired evening tests are sitting under it, you are in a much stronger position than you were ten minutes ago.

When can you leave over speed?

If your download speed drops below the minimum guaranteed speed you were given, and your provider has not sorted it within 30 days of you reporting it, the codes say you can leave without paying an early exit fee, and that goes for the landline or TV bundled alongside it too. There are narrow exceptions, so read your own provider's version rather than taking ours as gospel.

Two things trip people up here. The clock starts when you report the problem, not when it started, so report it early and get a reference number. And a connection that is merely slower than you hoped is not the same as one below the guarantee. Slow service also sits outside the automatic broadband compensation scheme, which pays out for total loss of service, missed engineer visits and late starts rather than for underperformance.

The fixes worth trying first

If the wired test was fine, the work is all indoors, and most of it costs nothing:

• Move the router. Out of the cupboard, off the floor, away from the television and the microwave. Central and high beats tucked away and low, every time.
• Use the 5GHz band for anything nearby. It is faster over short distances and gives up sooner through walls. Keep the slower band for the far corners of the house.
• Thin out what is connected. Cameras, consoles and a backup that quietly wakes up at the wrong moment all take their share.
• Consider mesh rather than a bigger router. Thick walls and long houses need more than one source of signal, and a single more powerful box rarely solves it.

Whether you can replace the provider's box at all varies by network, and on some it is not possible. Our guide on whether you can use your own router covers where that stands.

When the line really is the problem

A poor wired result puts it back with your provider. Report it, get the reference number, and let them run their own test, which they will do from their end rather than yours. Faults do happen, and a real one is often fixed quickly once someone has actually looked.

Sometimes the honest answer is that the line is doing what it was always going to do. Older copper-based connections lose speed over distance in a way full fibre does not, so a line that has never been fast may not have a fault at all. At that point the fix is a different connection rather than a better argument, and whether one exists depends on what has been built on your street. Our availability checker is the place to find out, and if you are not sure what speed you actually need before you go shopping, start with what broadband speed do I need.

One last thing worth saying plainly. Speed is the metric everyone fixates on and it is not always the one that is hurting you. A connection that is fast on paper but drops out twice an evening will ruin more video calls than one that is merely unremarkable and rock solid.

Frequently asked questions

Why is my broadband slower than the speed I was sold?

The number on the advert is usually an average measured at the busiest time of the evening, and roughly half the people who buy it get less. The number that binds your provider is a different one: the minimum guaranteed speed you were given before you signed. That is the figure to dig out, because everything you can actually do about slow broadband hangs off it.

Does wifi count when a provider tests my speed?

No, and this catches people out constantly. Your provider measures the line coming into the house, not the wireless signal bouncing around inside it. If your only evidence is a wifi test from the far bedroom, the complaint tends to go nowhere. Test over a cable first.

How many speed tests should I run?

More than one, on more than one day, and at least a couple in the evening when everyone is home. A single bad test proves very little. A fortnight of them at the same time of night is hard to argue with.

Will a new router fix a slow connection?

It fixes a slow house. It does nothing for a slow line. If the wired test is fine and the trouble only shows up two rooms away, better kit or a mesh system is the answer. If the wired test is also slow, a new router just moves the same speed around more elegantly.

Is my speed worse in the evening because of my neighbours?

Sometimes, yes. Networks are shared somewhere along the way, so heavy use in the evening can pull speeds down for everyone on that stretch. Full fibre generally handles it better than older copper-based connections, though no network is completely immune.