The ADSL and ADSL2+ line speed calculator

Use the form below to enter the line stats from your ADSL/ADSL2+ router.

This site will then calculate what sort of connection speed you should expect from your broadband connection, and give you a set of indicators as to whether your current stats fall within the normal range.

If you do not know where to get the attenuation, connection speed (bandwith) and noise margin (SNR) figures from for your ADSL or ADSL2+ router, then take a look at this guide for where the information is stored on a number of routers.

Why not check your connections speed

If the result from a speed test is massively lower than your connection, wander over to with a copy of your speed test results and router statistics.

The normal speed range displayed after the calculation reflects the speed you should expect to get for a line that is performing fairly well. The speeds alongside the varying target noise margins take into account your current noise margin, this can sometimes under estimate your speed if your provider uses power backoff techniques (e.g. Sky).


If after running your routers statistics through the checker you are told the results are bad, you may want to consider testing using the test socket at your BT Master Sockets test socket, i.e. remove the faceplate. If this improves the connection (sync) speed or noise margin figures and gives a better result in the calculator, consider investing in filtered ADSL faceplate, or the newer VDSL Interstitial faceplate. Alternatively disconnecting the ring wire or fitting an I-Plate to filter the ring wire alone may improve your speeds.