Choosing IB subjects: the best combinations
7 min read ยท updated 2026-10-13
IB Diploma students take six subjects, three or four at Higher Level (HL), and the HL choices matter most: universities set their requirements in HL subjects and grades. Start from the courses you might apply to and work backwards.
The rules
- โ One subject from each of groups 1-5: language and literature, language acquisition, individuals and societies, sciences and mathematics
- โ A sixth subject from group 6 (the arts) or a second subject from groups 1-4
- โ Three or four at Higher Level (about 240 teaching hours each) and the rest at Standard Level (about 150 hours)
- โ The Diploma needs at least 12 points from HL subjects, so weak HL choices are risky
Combinations by course
Examples from the University of Cambridge's published requirements; other universities are similar but check each one:
- โ Engineering: HL Maths Analysis and Approaches and HL Physics
- โ Computer Science: HL Maths Analysis and Approaches
- โ Natural Sciences (Physical): HL Maths, taken as Analysis and Approaches
- โ Medicine: HL Chemistry plus one or two of Biology, Physics and Maths, depending on the college
- โ Economics: strong maths, usually Analysis and Approaches
Maths: AA or AI?
Analysis and Approaches (AA) is the more algebraic course and the one most maths-heavy degrees ask for at HL. Applications and Interpretation (AI) suits students heading for social sciences, business or arts. If you might apply for engineering, physics, computer science or economics, keep AA open.
Common mistakes
- โ Taking three heavy HL sciences or maths without checking the workload
- โ Choosing HL subjects you dislike because they look impressive
- โ Picking Maths AI when your target degree asks for AA
- โ Forgetting the core: TOK, the Extended Essay and CAS add to the workload
FAQs
How many HL subjects do you take in the IB?๏ผ
Three or four, with the rest at Standard Level, for six subjects in total.
What IB subjects do you need for medicine?๏ผ
Usually HL Chemistry and HL Biology, often with Maths or Physics. Cambridge asks for Chemistry plus one or two of Biology, Physics and Maths, depending on the college.
What IB subjects do you need for engineering?๏ผ
HL Maths Analysis and Approaches and HL Physics at most universities.
Is IB Maths AA or AI better?๏ผ
AA for maths-heavy degrees such as engineering, physics and computer science; AI for social sciences, business and the arts.
Sources
Facts on this page were checked against these official sources on 2026-10-13.
Keep reading
More on IB
Want a specialist to help?
Try two free demo classes
The same tutor every week, matched to your child's exam board. No card, no commitment.
Book a free demo โ