How to Speed Up Slow Broadband

Not happy with your broadband speed? Find out the factors that can cause your connection to slow and how to fix them

The most popular question we get asked here at is 'How do I speed up my broadband connection?' So to help answer this we've compiled a list of things to check on your home setup. We've also included a few tips at the end for improving your wireless network speeds in case this is the cause of your problems.

  1. Understand your max speed
  2. Check you haven't been capped
  3. Check your software settings
  4. Check your hardware setup
  5. Check sockets and wiring
  6. Rule out wireless networking

Understand your broadband

If your provider's technical support are telling you that your line's fine and everything's working as expected, you may need to do some homework about your service.

Understand what your maximum speed is

Standard broadband over telephone lines degrades in speed the further the line is from the telephone exchange (in cabling length). While most deals are advertised as 'up to 17Mb', most telephone lines will be rated to achieve slower connection speeds. A similar principle even applies to fibre broadband. The majority of fibre offerings use FTTC (fibre to the cabinet), where the fibre connection is between the telephone exchange and your nearest roadside cabinet. The connection between the cabinet and your home is made over the standard copper phone cables. As a result, the promised 'up to 38Mb' speeds may actually be somewhat lower. Run a broadband speed test on your line using your postcode, for a second opinion we recommend If you are outside the UK use a local speed test website, such as if you are in India. Ensure that the speed you're told to expect is actually higher than the speeds you're experiencing - it may be that you're already achieving the fastest speed your line can expect.

Know the difference between bits and bytes

Make sure you're not confusing bits with bytes - Most broadband deals and speed tests are listed in terms of megabits or kilobits per second (Mbps or Kbps) while the progress speeds listed for most downloads are given as megabytes or kilobytes per second (MB/s or KB/s) there are 8 bits in 1 byte and a kilobit is 1000 bits while a kilobyte is 1024 bytes, so there is a significant difference in speeds listed in KB/s compared to Kbps - for example a line testing at 5Mbps download speed should expect to see maximum file download speeds of about 550-650KB/s or 0.6MB/s.

Check your download allowance

Make sure your broadband provider hasn't capped your speed because you exceeded the limits of your monthly usage allowance or traffic management policy. Many providers now reduce your speed rather than charging you for exceeding your allowance. You should be emailed a warning if you exceed your usage allowance, however if you've simply exceeded the traffic management allowance (often in place at peak times) you won't be informed, your speed will simply drop for a fixed number of hours (or until the peak period ends). Your provider's website should give you details of any traffic management policy in place and inform you of the effects of exceeding your usage allowance.

Check your computers and security

So you're happy that you understand the limits of your broadband service but it's still under performing? Make sure nothing you've installed and no one else on your wireless network is hogging your bandwidth.

Check for applications running in the background

Many applications run in the background on your computer and some of these will be quietly using your broadband connection for tasks such as installing updates or uploading data. Examples include the BBC iPlayer download version. Make sure that all unnecessary applications are shut down to prevent this. If this makes a difference, then add back each application until you identify which one is affecting your download speed. Having large numbers of browser windows or tabs open may also have an effect on your download speeds - try running the speed test with all other web pages closed, does this make a difference to speed?

Make sure your anti-virus software is up to date

Having up to date and operational anti-virus software is crucial as viruses, trojans and worms can use your broadband connection which can make your speeds seem to slow. Viruses and adware can also cause your computer to slow considerably which can make your broadband seem slow.

Other devices

It's not just computers that can use your broadband connection. TV on demand services such as through a Sky HD box might be using it to download TV shows, or your games console might be downloading updates or new content. These can all involve very large downloads and will slow your internet speed on your other PCs and tablets while they are completing. 

Password protect your wireless network

If your router works wirelessly, password protect your wireless network. Make sure that no one is hitching a free ride on your connection and taking up bandwidth which will reduce the speed you see, password protect and encrypt your wireless network to keep unwanted bandwidth hogs away. If you don't need to use your router's wireless network, consider turning it off completely (using your router's configuration interface).

Sockets and wiring

You know what's using your broadband but it's still slower than expected? Perhaps the wiring in your home's at fault, or maybe there's something you could install to squeeze out a little more speed.

Don't use telephone extension cables

Don't connect your modem/router using an extension cable. Poor quality extension cables are probably the number one cause of poor broadband speeds. Extension cables can massively increase interference on your line and cause broadband speeds to be lowered. The simplest way to solve the problem is to ditch the extension cable and connect the router directly to the phone socket and then use a long ethernet cable to connect your computer to the router (these can be purchased in any computer store and cost around £1 per metre), ethernet cables will not degrade the speed of your connection.

If you have to use an extension cable

If you have to use an extension cable, use a new, high quality cable and ensure you use the shortest cable possible - tangled and coiled telephone extension cables can cause interference. You can easily test if your extension cable is the problem - connect directly to the master socket, if this causes no improvement in connection speed, it's unlikely that the extension cable was the problem (however we recommend performing all tests below without extension cables plugged in if possible).

Use microfilters

Make sure all other phones/faxes/digiboxes/etc in the house are connected via a microfilter. Microfilters prevent other devices connected to your telephone system from interfering with your broadband signal. Every device connected to the phone system should use a microfilter. If you still have problems, unplug all devices and gradually add each back until you identify which causes the problem. If you're using free microfilters supplied by your broadband provider or with your router, consider paying for more expensive microfilters with good user reviews - it's possible one or more of your filter is faulty or of poor quality.

Use the BT Master Socket

Plug your modem/router directly into the BT Master Socket. The master socket is where your BT telephone line comes into the house. Most master sockets have a split across the front plate. The lower section of the plate can be unscrewed and inside is an engineer's test socket. If you remove the lower faceplate it will disconnect all the extension wiring in your property. You can then connect your modem/router using the test socket. If you get an increase in speed then your internal telephone wiring is causing interference that is lowering your speeds.

Fit a BT Accelerator

If test 10 made a difference, try fitting an I-Plate (also known as a BT Accelerator). Telephone extension wiring can act as a big aerial and cause interference on the broadband signal. An I-Plate is a device that fits into the bottom half of your split BT Master Socket and works by preventing the interference from your internal wiring. This can have significant positive effects on your speeds. An I-Plate costs around £10 and can be DIY fitted. Note, newer master sockets with 'Openreach' written on them will not benefit from an I-Plate as the technology is already built in.

Check for electrical interference

Electrical equipment can cause interference. Electrical equipment can cause real problems for your connection, anything with a motor or pump can particularly be an issue. Try turning off electrical devices to see if they are interfering. If possible keep your router/modem away from other electrical equipment. BT have shown that faulty fluorescent lighting and even christmas tree lights can drastically reduce broadband speeds in some cases. Experiment with turning off devices.


Perhaps a new router could help, maybe you can get a free regrade to a better broadband speed or maybe now's the time to consider switching to a faster broadband provider.

Upgrade to a good quality router

If you are using a cheap modem or router and your provider allows it, consider replacing with a newer higher quality router. A cheap radio gives a poorer sound reproduction than a quality radio, in the same manner a cheap modem or router can sometimes be the cause of a poor broadband experience. Investing in a higher quality router can lead to improvements in speed and reliability, especially on poor quality telephone lines. If you're not sure, look online for user reviews of your make and model of modem or router - if there are problems it's likely that reviews will show this.

This can especially be an issue when you haven't switched broadband suppliers for quite some time as you may be using a router that doesn't support more recent upgrades to your telephone exchange. If in doubt, ask your supplier's tech support team.

Upgrade your broadband package

It's always worth speaking to your broadband supplier to see if your speed can be increased, this is particularly relevant for people who have had their connection for a long time and may still be on deals capped at a speed below that which your line can support.

You may be lucky enough to live in an area that's recently been upgraded to super-fast broadband technology which is much less dependent on distance from the telephone exchange. Our availability checker can confirm what's available in your area.

Improving speeds over wireless access

Quite often people blame their broadband provider for poor connection speeds when actually the problem is a poor quality wireless network causing the issues. Here are our top tips for improving your wireless network speeds.

Use a wired connection instead

Connecting to your router via a wired connection rather than wireless can improve your speeds. Wireless networks can be subject to interference and are affected by the size and composition of your home. Thick walls on old houses can be a particular problem. A wireless network that has lots of interference can make your broadband connection seem slow. Required security measures, such as encryption, also add an overhead to wireless connections that is not necessary for a wired connection. Connecting using a wired Ethernet (network cable) connection gets round the problem and can improve speeds, but it obviously is less flexible than a wireless connection.

Test how much slower your wireless network is

If you definitely want to connect via wireless, run speed tests connection directly by network cable and again using the wireless network. If there are significant differences, consider the tests below.

Upgrade your wireless equipment

If you are connecting via wireless and are having problems then consider getting a better aerial, using a network extender or upgrading your router and devices to use the newer, more robust 'AC'-rated wireless standard. Upgrading the aerial on your wireless router and if possible on your computer can extend the range and reliability of connection. Another option is to use a wireless network extender; these work by boosting the wireless signal into areas of poor signal. The newer 'AC'-rated wireless standard (as used in routers like the BT Home Hub 5) provides greater range and faster connections, however all your devices will need to support the 'AC'-rated networks in order to see the benefit. USB adapters and expansion cards are available to upgrade some older devices (but not smartphones or tablets), while 'N'-rated devices or older will still be able to connect at their previous range and speed.

Change the channel

If other wireless networks are in range, change your wireless router to use a different channel to avoid interference. We recommend using channel 1 as this is usually free and won't interfere with the standard channels used by most popular routers.

Have you found this guide useful?

We hope you've found this guide useful and that it has helped you understand the factors than can affect your broadband speed. Maybe you can spare just 2 minutes to help us and complete our 2 minute survey, thanks!

If you're still having problems with your broadband speed, our guide on how to complain to your supplier and access alternative dispute resolution may also be helpful.