AS level, or Advanced Subsidiary Level exams are the first half of an 'A Level'.

AS Levels are normally taken in Year 12, with most schools asking students to choose between 3 and 5 AS Levels. These were introduced to give students more choice in their subjects.

AS Levels comprise of 3 units.

After doing your AS Level (passing all your AS exams and course work) you can then do the second year, called A2 Level.

An entire A level is made up of 6 units. So you do a further 3 units in the second year.

AS Levels mean you don't have to buckle down and choose exactly what you want to do at 16. It gives you another year to get a little bit deeper in the subjects you choose, and see which ones you'd like to carry on forward.