How many IB subjects do Diploma Programme students choose?

Full Diploma Programme students study six subjects alongside TOK, the extended essay, and CAS. They normally select one course from each of Groups 1 to 5, followed by an arts subject or another permitted subject from the other groups. At least three and no more than four subjects are taken at HL, with the remainder at SL. Interdisciplinary subjects can satisfy requirements across two groups, but students still complete six subjects overall. Schools may restrict available combinations because of staffing, timetable blocks, or class sizes.

Should I choose three or four HL subjects?

For most students, three HL subjects provide the best balance between specialization and workload. Four HLs are permitted, but each HL is designed for approximately 240 teaching hours compared with 150 at SL. A fourth HL may be reasonable when a school requires it initially, when a student is deciding between two subjects, or when a specific admissions situation justifies it. It does not automatically make an application more competitive, particularly if it lowers the final grades. Discuss the decision with your DP coordinator and identify exactly what the fourth HL is intended to achieve.

Which IB subjects should I take for medicine or engineering?

Requirements vary by country and university, so there is no universally correct combination. Medicine programmes often require Chemistry HL and may also require Biology HL, while engineering commonly requires Mathematics and Physics at HL. Some institutions specify Mathematics: analysis and approaches rather than accepting either IB mathematics course. Requirements can also include particular grades, overall points, admissions tests, or national recognition conditions. Check several current university admissions pages before choosing and obtain written clarification when the wording is uncertain.

Is Mathematics AA harder than Mathematics AI?

Neither course is universally harder because they emphasize different forms of mathematical thinking. Mathematics: analysis and approaches gives greater emphasis to analytical methods, algebraic reasoning, and mathematical argument. Mathematics: applications and interpretation emphasizes modelling, statistics, technology, and mathematics in practical contexts. Difficulty depends on the level, the student's strengths, and the type of problems they prefer. University requirements matter more than general difficulty claims, because some mathematics-intensive degrees specifically require AA HL.

Can I change an IB subject after starting the Diploma Programme?

A subject or level change may be possible, but the decision is controlled by the school rather than guaranteed by the IB. Changes are easiest early, before substantial teaching and internal assessment work have been completed. Moving into an HL course can require catching up on additional content, while changing subjects may involve an entirely different assessment structure. A late change can also affect university prerequisites, the extended essay, and the school's examination registration. Speak to the subject teachers and DP coordinator immediately rather than waiting for the next reporting period.

How should I use IB subject guides before choosing subjects?

First, make sure the guide or subject brief applies to your intended examination year. Review the syllabus outline, teaching hours, assessment components, internal assessment, and differences between SL and HL. Pay attention to the tasks you will perform, not merely the topics you will study. Compare this information with sample lessons or exam-style questions to judge whether the course suits your skills. Finally, check the official details against your school's implementation because available options, scheduling, and teaching sequences vary locally.

Back to all posts

IB Subject Guides: How to Choose Your Subjects

• 29 Jul 2026•9

Join 650k+ students breezing through the IBReady to breeze through the IB?

IB Subject Guides: How to Choose Your Subjects | RevisionDojo

Back to all posts

IB Subject Guides: How to Choose Your Subjects

• 29 Jul 2026•9

Choosing IB subjects requires more than selecting the classes you currently enjoy. The strongest combination satisfies Diploma Programme rules, supports likely university courses, matches your abilities, and creates a workload you can sustain for two years.

Start by reading the current IB subject guides or subject briefs for your examination session. Then compare university prerequisites, your school's available courses, assessment formats, and your realistic HL capacity before confirming your choices.

Understand the IB Diploma subject rules

The Diploma Programme consists of six subjects and the DP core: theory of knowledge (TOK), the extended essay (EE), and creativity, activity, service (CAS). Under the official DP curriculum structure, students normally choose one course from each of the first five groups, followed by an arts course or another permitted subject from the other groups.

Students take three to four subjects at Higher Level (HL), with the remainder at Standard Level (SL). The IB recommends 240 teaching hours for HL and 150 teaching hours for SL. HL and SL are graded on the same 1-7 scale, but HL covers a greater body of knowledge, understanding, and skills.

Level	Typical teaching hours	Best suited to	Main consideration
HL	240	Subjects central to a university plan or major academic strength	Greater depth, content, and time commitment
SL	150	Subjects needed for breadth or supporting knowledge	Still rigorous and contributes equally to the subject-point total

The usual pattern is three HL and three SL subjects. Taking four HLs is permitted, but it should solve a specific admissions or scheduling problem rather than serve as a general display of ambition. The RevisionDojo HL and SL comparison explains the practical difference in depth and workload.

The six IB subject groups

Group	Area	What to consider
1	Studies in language and literature	Your strongest academic language, reading demands, and literary or textual analysis
2	Language acquisition	Your previous experience and the correct placement in language B or ab initio
3	Individuals and societies	Interest in evidence, argument, human behaviour, institutions, or social systems
4	Sciences	University prerequisites, mathematical confidence, practical work, and scientific reasoning
5	Mathematics	Whether a future course expects Mathematics: analysis and approaches or accepts applications and interpretation
6	The arts	Creative interests, practical production, performance, and sustained portfolio or project work

The arts are not compulsory in the regular subject pattern. Students may generally replace Group 6 with an additional language, individuals and societies subject, or science, subject to the combination rules and school availability. Interdisciplinary courses can satisfy more than one group, but the student still completes six subjects.

The IB publishes a current list of DP subjects and their SL or HL availability. Your school will normally offer only part of this list, so confirm availability, timetable blocks, class-size conditions, and examination sessions with the DP coordinator.

How to choose the right combination

Check university requirements first

Research several plausible degrees and countries, not just one preferred university. Admissions requirements can specify an exact HL subject, mathematics course, science combination, language, or minimum grade. For example, engineering courses commonly place greater emphasis on mathematics and physics, while medicine requirements vary significantly between countries and institutions.

Use the IB university recognition database and current university course pages, then confirm unclear requirements directly with admissions teams. A subject that is interesting but unnecessary can be changed later; a missing prerequisite may prevent an application entirely.

Put essential subjects at HL

Once prerequisites are identified, place required subjects at HL. Use the remaining HL places for subjects in which you have both genuine interest and evidence of strong performance.

Do not choose HL solely because a subject is considered prestigious or supposedly easy. Guidance on selecting IB HL subjects can help you compare interest, attainment, and future relevance.

Read the assessment details

A course title does not reveal how the subject feels week to week. Consult the correct subject brief or guide and examine:

syllabus content and prescribed themes
examination papers and command terms
internal assessment requirements
practical, oral, performance, or portfolio components
differences between SL and HL
the first-assessment year of the syllabus

This matters because students with similar grades may prefer different assessment styles. One may perform well in timed essays, while another is stronger in calculations, oral communication, laboratory work, or long-term projects.

Balance the total workload

Consider all six subjects alongside TOK, the EE, CAS, internal assessments, and activities outside school. Several writing-heavy or project-heavy courses can create overlapping deadlines even when each subject is individually manageable.

Ask current teachers what your school calendar actually looks like. Use the RevisionDojo guide for students who are undecided to build breadth without selecting subjects randomly.

Common subject-selection mistakes

Avoid these recurring errors:

Following friends: Their strengths, goals, and timetables may be different.
Relying on difficulty rankings: Teaching quality and personal aptitude affect difficulty considerably.
Ignoring the exact mathematics course: Mathematics AA and AI are not interchangeable for every university programme.
Selecting four HLs without a reason: The additional workload can reduce performance across the diploma.
Using an outdated guide: Syllabuses and assessments change, so match resources to your examination year.
Assuming every IB subject is offered: Course availability is determined locally by the school.

Before finalizing, test your likely subjects using the RevisionDojo IB resource hub. Sample Study Notes can show the conceptual level, while the Questionbank practice guide explains how exam-style questions reveal whether you enjoy applying the material.

A practical final checklist

Confirm that your combination:

meets the IB Diploma group and HL requirements
is available and timetabled by your school
preserves the university routes you may pursue
places required or strongest subjects at HL
matches your preferred assessment styles
remains manageable alongside the DP core
uses guides for your correct examination session

Conclusion

The best IB combination is not the one that appears most difficult. It is the one that satisfies official rules, protects university options, reflects your strengths, and remains sustainable across two demanding years.

Use official IB subject guides for requirements and assessment details, then verify your understanding through RevisionDojo Study Notes, Questionbank questions, and Jojo AI. These tools can help you compare the real academic demands of subjects before committing to them.

Sources and referenced URLs

Add as a preferred source on Google