A level is three subjects studied in depth, IB is six. IB also includes a compulsory core programme consisting of Theory of Knowledge, an Extended Essay and an evaluation of a student’s CAS (Creativity, Action and Service). These are mandatory requirements to receive the diploma. This makes the IB considerably harder.
The A levels only consist of teaching students specific content and testing their knowledge through exams. The IB, on the other hand, is much more than that. It not only conducts exams but also emphasises on writing and developing critical thinking skills. Students are required to engage in research and much more.
A levels are graded by letters, with A* being highest, while IB uses a points system (the perfect score is 45 points), where 24 points and above secures an IB Diploma.
Students who wish to study in the UK generally pick the A levels. While the IB is also highly recognised in the UK and globally, A levels is preferred. Additionally, transitioning from ICSE to IB could be a little more difficult than transitioning to A levels. However, the IB not only gives you college credit but also offers a much more holistic education and prepares you for university. Depending on your goals for the future, such as the country you want to study in, you will have to pick a curriculum accordingly.