Broadband speed test: Which? expert advice

Don't just go by your provider's promise on broadband speed. Use the Which? free speed test to investigate.

We explain how to use the speed checker below – and if your broadband isn't as fast as it should be, we give you some simple steps you can take to speed up your connection. 

How to use our broadband speed checker

For the most accurate results, use an ethernet cable to connect your computer to your router before running the test. If you need to test wirelessly, get as close to your router as possible.

You should also make sure nothing else is using your internet connection or running on your computer when you do the test. 

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What do the broadband speed test results show?

The tool measures the response time – also known as latency – of your broadband connection, as well as your download and upload speeds.

The response time:

• is measured in milliseconds (ms)
• shows how quickly you get a response after you've sent out a request.

More responsive connections are those with a low number of ms (meaning they take less time to respond). This is needed for applications where timing is everything, such as interactive video games.

The download speed shows the rate at which data is transferred from the internet to your device – how quick it is to access a newspaper article online or stream music, for example.

The upload speed shows the rate that data is transferred from your device to the internet – how quick it is to upload a photo or document to an email, for example.

Download speeds are usually of more interest, as most tasks require you to download information, for example searching online for information. 

However, if you use your broadband connection for video calls or online gaming, keep an eye on the upload rate, too, as it's essential for both.

It's important to note that the speed test results only represent a snapshot of your broadband connection at the time of testing. To build an accurate picture, we would suggest you run several tests during a single week, in peak use time (between 8pm and 10pm) and during off-peak times.

The results also only show the speeds you're getting on the device you're using for the test – the speed your provider is delivering to your home may be higher, especially if you're performing the test wirelessly at some distance from your router.

What you can do if your broadband speeds are slow

If your speeds are significantly less than you expected, there are steps you can take to improve things – get started by checking our advice on Speed up slow broadband.

However, if you've done everything you can to speed up your connection and you're still getting a lower speed than you were promised, your broadband provider may be in breach of contract. 

We suggest calling your internet service provider (ISP) as a first step to see what it can do. Start by providing evidence of your internet speeds – it's a good idea to keep a diary of interruptions and to regularly use the speed checker tool to build up a true picture of your service. 

If your broadband contract started after March 2019 and you're with one of the providers that has signed Ofcom’s voluntary code of practice (BT, EE, Plusnet, TalkTalk, Utility Warehouse, Virgin Media and Zen Internet), your provider must give you a minimum guaranteed speed when you take out a new contract. If your speed drops below this, your provider must improve it within a month – if it can't, it must allow you to exit your contract penalty-free.

If you're not happy with your ISP's response, follow our guide on how to complain about your broadband speed.

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If you're unhappy with your current broadband provider, consider our top-rated provider instead. We can't guarantee it will give you the fastest speeds, but it convincingly beat 11 other major providers in our unique Which? broadband satisfaction survey and is a Which? Recommended Provider.

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