Preliminary and HSC courses each have a unit value which indicates how many hours should be allocated to study at school.
1 unit = 60 hours of course work per year = 50 marks
2 units = 120 hours of course work per year = 100 marks
To gain an HSC, students must have completed a minimum of 12 units of Preliminary courses and 10 units of HSC courses. All courses in the HSC have a unit value. Most courses are 2 units so a typical student will complete 6 subjects in Year 11 and 5 subjects in Year 12.
Students must satisfactorily complete the Preliminary course (usually studied during Year 11) before they are eligible to commence the corresponding HSC course (usually studied during Year 12). English is the only compulsory, 2 unit subject for the HSC.