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Your broadband speed - the basics

Summary: Want to know a bit about how broadband works? Here we explain how the technology delivers a flexible service, giving you the best experience available at all times
  1. What speeds should I be getting?
  2. Why does my speed change?
  3. What speed am I getting now?
  4. More information

1. What speeds should I be getting?

Your broadband will always try to connect at the highest possible speed available on your telephone line, which is why we refer to our broadband services as 'Up to' a certain speed.

Our standard broadband (ADSL 1 & ADSL2) speeds are determined by:

  1. Distance from your telephone exchange: A standard phone line can be several miles long, from your local exchange to your address. Shorter phone lines can support higher speeds. So, the longer the phone line the slower the speed.
  2. If your telephone exchange has been upgraded: Many exchanges have been upgraded to ADSL2+, meaning that faster speeds can be provided.
  3. The quality of your telephone line: A phone line consists of 2 insulated copper conductors twisted round each other. Damaged, corroded copper or poor connections between cables will mean poorer speeds.
  4. Your wholesale broadband product:
    • ADSL2+ offers speeds up to 17Mb
    • ADSL1 offers speeds up to 6Mb

Our fibre broadband technology is capable of up to 76Mb speeds. What you'll actually get is determined by:

  • Distance from your green cabinet: Fibre optic cabling runs from your local telephone exchange to your nearest green cabinet. A short standard copper phone line then runs from the green cabinet to your address. Shorter phone lines can support higher speeds. So, the longer the phone line the slower the speed.
  • The quality of your phone line: The short length of copper phone line between your nearest green street cabinet and your address consists of 2 insulated copper conductors twisted round each other. Damaged, corroded copper or poor connections between cables will mean poorer speeds.
  • Your broadband product: Our Unlimited Fibre product sold from 10th June 2014 has a maximum download speed of 40Mb, though you may see results through the speed checker showing your line is capable of higher speeds than this. If so, you may want to upgrade to Unlimited Fibre Extra.

When you sign up, move house or switch broadband product we'll give you an estimate of the speed you should be getting. We'll show this to you as:

  • A single estimated speed - e.g. 6Mb
  • An estimated speed range - e.g. 3.5 to 5Mb

Speed estimates represent the maximum speed your line should be capable of under ideal conditions. You can see your estimate and the speed you're currently getting at High Speed Broadband in My Account.

If the actual speed you get is much lower than this see our troubleshooting guides or watch our Broadband speed checks video to find out what to do next.

*If your estimated speed is below 4Mb, we'll provide an ADSL1 service even if ADSL2+ is available. This is to give you a more stable and reliable service and a better broadband experience.


2. Why does my speed change?

During the first 10 days of your broadband service

At first we won't know exactly how fast your broadband will be. To find out, a number of tests are run from your telephone exchange which will cause your speeds go up and down. You may even get disconnected a few times. Don't worry, this doesn't mean there's a problem, so please bear with it. During this time we'll find the best balance between speed and reliability for your line.

You can help the testing process by rebooting your router (switch it off and on again) three or four times over the first 10 days. You'll get better results if you can do this in the morning.

After the first 10 days

Your line will settle down to a speed close to the estimate we gave when you signed up. Small changes are normal and nothing to worry about.

If there's a problem affecting your connection (see the table below for info about some of the things that can happen), your line speed will be reduced to try and keep your service stable.

After a problem is fixed, it can take up to 3 days for speeds to return to normal.

This process is known as Dynamic Line Management, you can read more about it in our Broadband Terminology guide.

What sort of problems cause speeds to change?

Cause How this can affect your broadband speed
Broadband Faults Any broadband fault can cause a drop in speed. This is particularly common in cases where broadband is disconnecting regularly. As mentioned above, it can take up to 3 days of stability before broadband speeds return to normal.
Telephone Faults

Broadband is supplied over your telephone line, so it needs the line to be working properly. Subsequently, it's common for telephone faults to cause problems with broadband service. You may see slow speeds or you might not be able to connect at all.

In nearly all cases, once the telephone line is fixed the broadband will be too. Connection problems tend to clear up immediately, with slow speeds it'll be a few days before your speed gets back to normal.

Wireless The position of your router/computers and the channel that your wireless network broadcasts on can have a big impact on your wireless signal strength. A poor quality or low strength signal will reduce the speed you're connected to the router and as a result of this, the speed at which you can download data. See How to improve your wireless signal for help with this.
Wrongly setup microfilters If you've not connected these up properly you'll not get the best broadband experience. It's a common cause of intermittent connection and speed problems. You should avoid using long phone extension cables too. See Microfilters - how and why for more help.
Bad weather Heavy rain or thunderstorms can play havoc with broadband speeds. In fact, a severe storm could even damage your equipment permanently. We'd suggest unplugging your equipment from the phone line and power socket. You can plug them back in after the storm has passed.
Electrical interference Household equipment (either yours or your neighbour's) can cause interference which often affects broadband speed. Things like TVs, alarms, fairy lights and set-top boxes are known to cause problems.
Your computer

Older machines can have trouble running newer software and operating systems, giving the impression that the broadband connection is slow.

If your computer has picked up something nasty it can slow everything down.

Make sure you've got the latest protection installed. We recommend Plusnet Protect - powered by McAfee - find out more.

3. What speed am I getting now?

To check your speed run a few tests at

If the results are slower than you'd expect (e.g. considerably lower than your original estimate) these guides will show you how to troubleshoot problems:

For standard broadband: Speed troubleshooting - standard broadband.

For fibre optic broadband: Speed troubleshooting - Plusnet Fibre.


4. More information

Interested in finding out more about broadband and how it works? There's loads of guides to choose from, check out the links below:


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