A level grades are also sometimes converted into numerical scores through the UCAS university admission system. A target score will often be given instead of grades when making a university offer. It allows greater flexibility to the students: for example, if a university gave a 280 point offer (rather than the equivalent BBC), this could also be achieved through the combination ABD, which would not otherwise have been sufficient to meet the offer.
Under this system, an A* grade at A Level is worth 140 points, an A grade 120, a B grade 100, a C 80, a D 60, and an E 40 points. AS Level qualifications each earn half of this. However, if a student continues a subject from AS to the full A level, the points will not be counted from both AS and A2: only the A2 grade will count towards the UCAS tariff.
You can also get UCAS points for other things, like music grades and key skills level three.
A more comprehensive list of points awarded can be found here: http://www.tcea.org.uk/Documents/ucas_points_system.htm or at the UCAS website here: http://www.ucas.com/candq/tariff/index.html#tables