The aim of this article is to highlight what we mean by "broadband speeds", how they are measured, what can affect your broadband speeds and how you can improve them.
What do we mean by "Broadband speeds"?
When talking about broadband speeds we are referring to how quickly you can get information from the Internet to your computer. This is known as your download speed. How quickly you can send information from your computer to the Internet is known as your upload speed. We measure broadband speeds in Mbps (Megabits per second) sometimes referred to as "Meg" e.g. 2Mbps or 2Meg.
Comparison of our Broadband speeds - 7Mbps, 16Mbps and 76Mbps.
We offer three types of broadband service.
ADSL "up to 7Mbps" products are available on all exchanges in the UK. As with all broadband, actual speed is dependent on the length and quality of your telephone line. Upload speeds are "up to 448Kbps" on Lite, Active and Pro and "up to 832Kbps" on our business services, Office and Office Max.
ADSL2+ broadband services provide "up to 16Mbps" download speeds across large parts of the country (approximately 70% of the UK population as of Summer 2011). ADSL2+ also offers faster upload speeds of “up to 1Mbps”.
Fibre Optic Broadband is our latest range of superfast broadband services and is being rolled-out nationwide with the aim of reaching 40% of premises by Summer 2012.
To find out which broadband services are available to you, please use our "broadband speed checker".
How to check available broadband services and estimated download speeds?
Enter your phone number and/or your post code and the Broadband Speed Checker will show you available broadband services with an estimate of your maximum download speed (or how quickly you can download information from the Internet).
This speed estimate is generated using telephone line data from previous broadband service installations where we have established what broadband speeds the telephone line is capable of supporting. This speeds is often referred to as the "line rate" or "sync speed". This is a theoretical upper limit for your line based on a set of conditions. The speeds you experience on a day-to-day basis will be less than this and will vary at different times. The download and upload speeds delivered are often referred to is often referred to as "throughput speed" and represents the actual amount of data being transferred.
Note that estimates based on post codes are less accurate than telephone numbers as they are less specific to a location.
What "throughput speed" will I get?
The table below provides an indication of the throughput speeds based on the line rate (sync speed) that your telephone line can support.
|ADSL Line Rate
||Minimum Downstream Speed (Throughput)
|0 to 288kbps
||100kbps to 250kbps
|288kbps to 576kbps
||100kbps to 500kbps
|576kbps to 1152kbps
||400kbps to 1000kbps
|1152kbps to 2272kbps
||800kbps to 2000kbps
|2272kbps to 4544kbps
||1200kbps to 4000kbps
|4544kbps to 8128kbps
||2000kbps to 7150kbps
|8128kbps to 24384kbps
||4000kbps to 21000kbps
The low end of the speeds in each band reflects the speeds you may expect during peak usage times.
Fluctuation in broadband speeds is expected to occur within the first 10 days of service whilst your line speed adapts to the maximum it can reliably support. Please note that when we provide you with a broadband speed estimate we have based this on a range which is equivalent to the access line speeds achieved by the majority of our similar customers.
Fibre Optic Broadband
Minimum downstream throughputs are based on line rate and are provided on a "best efforts" basis. They aim to provide speeds at and above the minimum downstream levels as described in the table for 90% of the busiest 3 hour period of the day. The busiest 3 hours of the day is determined by constant measurement of the network traffic between the DSLAM (the new green street cabinets) and handover points to the Zen Internet network.
Customers taking services with Elevated Minimum Downstream Speeds have their traffic given preferential weighting at a routing point in the network. This gives a higher throughput speed during periods of heavy internet use across the shared network.
||Minimum Downstream Speed
||Fault Threshold Rate (FTR)*
|Fibre Office Plus
||70% of line rate
||Service not available on lines unable to support 15Mbps and above
|Fibre Office Plus
* The FTR is based on the speed that the line is able to synchronise to on first provision (following a period of around 10 days in which the line is allowed to stabilise). If your service speed drops below the FTR please contact our technical support team who will investigate the fault.
What can affect broadband speeds?
Although you'll get a maximum download speed for your broadband service from it will be dependent on a range of factors, and subject to survey and availability. Broadband speeds can be affected by a number of factors including, but not limited to, the following:
- The length of your telephone line to your local BT Telephone exchange
- The quality of the internal telephone wiring in your home or business
- The age of your computer or broadband router
- If you're connected to the broadband router directly or via wireless
- Number of applications or programmes you are running on your computer
- The speed of the Web site you're downloading information from
- The number of people trying to download the same information as you from the same Web site
- Weather conditions
- Seasonal decorations e.g. Christmas tree lights
- The quality of the line e.g. degradation of your line over time may result in a reduction in the broadband speeds you receive
For more information on slow speeds visit our Troubleshooting Slow Speeds article
How can you improve your broadband speeds?
Sometimes making the smallest of changes can make a significant improvement on your broadband speeds. If you would like to increase your broadband speed you could try the following:
- If your computer or broadband router is old then upgrading them may improve your performance
- If connecting wirelessly to your broadband router:
- try plugging directly into your broadband router to see if there's any improvement, if there is then you could try moving the location of your router
- make sure that your wireless connection is secure. If other people are using your connection then it will definitely slow your own broadband speed down
Want to find out more?
For further information on how we can help you find the right broadband service please call 0845 058 9000 (or alternatively 01706 902000) or fill in the enquiry form.