By age 14 most UK schools will progress to study GCSEs over a 2 year period. The variety of subjects will depend on the size of the school. Most pupils will be expected to study a minimum of 8 subjects, including at least maths, English, 3 sciences and a modern language. Schools will often offer blocks of optional subjects beyond the core group.
Some schools start a small range of GCSEs as early as 13 allowing a longer period and extra subjects scheduled over 3 years such that it is not uncommon for pupils to pass 11 or more GCSEs
Students who excel in sciences or maths will be able to study Additional Maths and 3 separate sciences instead of combined science.
For some years, private schools have moved from the standard GCSEs to the ‘international’ version, the iGCSE, which is regarded as a more robust curriculum. In 2015, the UK Government removed the harder iGCSEs from their league tables in order to flatter the comparable results of State schools. Most private schools have no intention of dropping the iGCSE and would rather boycott Government league tables instead.
Most GCSE curriculums last for 2 years and schools will not generally admit new pupils at age 15 half way though unless they agree to start the two-year course with students of the year group below. Sometimes we can find boarding schools to offer 1 year intensive GCSEs in which case the student would study a maximum of 6 subjects over 1 year.