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The definitive guide to broadband speed tests

Wednesday, March 23rd 2016

Broadband providers promote their packages by quoting the optimum speeds available, but how fast is your connection in reality? By using an internet speed test, you can find out your actual speed – and see how close it is to the speed you’re paying for.

Performing a speed test can be revealing: if you’re only reaching low speeds on a purportedly fast connection, you're paying for a service you don't get.

Our speed test

Our broadband speed test allows you to discover your download and upload speed quickly and easily. Its simple interface is easy to use, with just a single button to start the test once you’ve entered your postcode and a small amount of information about your broadband.

You can find it at the link below, but for more information about how the test works and what your results mean, keep reading our guide.

Run speed test →

How does it work?

With our accurate and superfast speed test, you can get your download and broadband speeds in less than a minute; but how does it work?

Download test

There are four stages that the test goes through to measure your download speed:

  1. Before the test begins, it determines which is the nearest web server to your device. A closer web server gives a better indication of your broadband speed than one further away, as the communication delay is shorter.
  2. Once the web server has been chosen, the test then generates a tiny data packet for your device to download. The type of connection you’re using determines the size of the data packet it downloads, so if you’re on a fibre optic line, the test will download a larger file than if you’re connecting via standard ADSL or mobile.
  3. The data packet is downloaded hundreds of times during the test (averaging at about 30 times per second) to give a large number of results for the next stage in the speed calculation.
  4. Once the previous steps have been completed, the test takes the results provided by the packet download and generates an average rate. The average is then reported back to you as the speed your connection has achieved.

Upload test

The upload test works in a similar way to the download test; only this time your computer is sending data to rather than receiving data from the server.

  1. The test first generates a small packet of random data and sends it to the same web server used for the download test.
  2. From this initial packet, the test then creates another data packet that is appropriate to the type of connection you’re using.
  3. As with the download test, this data is sent hundreds of times to give a range of results. These are then averaged to find the upload speed of your connection.

Run speed test →

Getting meaningful results

UK average broadband speeds by provider

Our speed test has been designed to be as simple to use as possible, but any speed test can offer more meaningful information if it has some context, and ours is no different.

Who provides your broadband?

Telling us who provides your broadband gives your speed results context with other people in your area who use the same provider. We’ve included all the major UK Internet Service Providers (ISPs) in a dropdown menu, along with a selection of the more niche ISPs. Big names like BT and Virgin Media are covered, but Zen Internet and Eclipse are in the list too.

Advertised vs. actual speed

Broadband providers aren’t shy of showing off their download speeds, and it’ll often be the first thing you’ll see when hunting for a broadband connection. The numbers are big and bold, and while they might seem impressive at first, it’s worth bearing in mind that the advertised figures are the best speeds you could attain, not the likely ones.

By selecting the speed advertised by your current provider, you can help the test recognise the type of broadband connection you’re using. If you don’t know your advertised speed, don’t worry, the test will work just as well – it may just take a few seconds longer to generate the results.

Your postcode

The download and upload speeds you’re capable of reaching are largely determined by where in the UK you live. While it’s not always so clear-cut, rural areas generally receive lower broadband speeds than urban areas, and fibre roll out to these places often takes longer too.

Your postcode isn’t taken into account when generating the results of the speed test. Instead, we use your postcode and speed to create a list of the average broadband speeds achieved across the UK, by provider. This way you’ll know the actual speeds that broadband providers offer; not just those that are advertised.

Run speed test →

Your postcode is safe with us, as we’ll never share your personal information with anyone. If you’d like to find out more about our privacy policy before you undertake a speed test, you can find the information at the link below.

Privacy Policy →

Your broadband type

There are all sorts of ways to get online, from super-quick fibre optic to mobile-based 3G. Each type of connection provides a different level of speed, and you can help the speed test generate your results faster by letting it know what kind of broadband you’re using.

If you’re not sure which broadband connection you’re on, take a look at the list below for a few ideas.

  • Standard broadband: Copper cable-based connection, otherwise known as ADSL2+
  • Fibre optic: Fibre cable and light-based connection, known for its high speed
  • 3G mobile: Smartphone-based, wireless internet network, also dongle-based
  • 4G mobile: Smartphone-based, high speed wireless internet network
  • Satellite broadband: Satellite-based, slow, used in areas outside standard networks

How to use the results

Now that you’ve got your download and upload speeds, there are a few extra steps you can take to improve your connection.

Check the average speeds

When you receive your results, you should see an average speed indicator below your download and upload numbers. This indicator shows you the average speed other people using your broadband provider have achieved.

Alongside this, the main speed test page contains a top ten list of the best broadband providers as rated by download speeds. If your speed is less than the UK average, you may want to switch to a provider who can offer you a better service. This brings us nicely to…

Compare what is available

Slow speeds are frustrating, especially for those of us who use our broadband all the time. If you’re getting slow downloads, it may be time to switch to a new broadband provider.

To see if you could be better off, it’s easier to use an Ofcom-accredited comparison service rather than just looking at each provider individually. We’ve included our comparison table just below, so you can compare different broadband providers. Clicking the dropdown menu allows you to change providers and packages.

  • Broadband
    Max download speed52Mb
    Max upload speed9.5Mb
    Monthly usageUnlimited
    Home Phone
    Daytime calls10.24ppm
    Evening calls10.24ppm
    Weekend callsInclusive
    Pricing & Contract
    Set-up cost£9.99
    Contract length18 months
    First year cost £369.87

    per month
    includes line rental

  • Broadband
    Max download speed38Mb
    Max upload speed9.5Mb
    Monthly usageUnlimited
    Home Phone
    Daytime calls9.50ppm
    Evening calls9.50ppm
    Weekend calls9.50ppm
    Pricing & Contract
    Set-up cost£59.95
    Contract length18 months
    First year cost £359.95

    per month
    includes line rental

    0800 840 5394 0800 840 5394
  • Broadband
    Max download speed100Mb
    Max upload speed6Mb
    Monthly usageUnlimited
    Home Phone
    Daytime calls9.94ppm
    Evening calls9.94ppm
    Weekend callsInclusive
    Pricing & Contract
    Set-up cost£20
    Contract length12 months
    First year cost £428

    per month
    includes line rental

    0808 168 4947 0808 168 4947


Knowing the speed of your broadband connection keeps you informed about the level of service you’re receiving. If you’re on a high speed fibre tariff, but only getting slow, ADSL-level speeds, it might be worthwhile switching to a new provider, or contacting your ISP to ask them what’s going on.

If you’re looking for ways to quickly speed up your broadband connection, our guide on making your broadband faster could be a great help.

And don't forget, Cable.co.uk now produces in-depth broadband reviews of every major UK broadband package, so check them out if you need more information.

Run speed test →

Why do we need your postcode?

Once you enter your postcode, Cable.co.uk will perform a live lookup and check all the available providers in your area.

This ensures you receive accurate information on the availability of providers and packages in your area.

Your information is safe with us. We won't share your postcode with anyone. Guaranteed.