What SL and HL actually mean
IB Diploma students take 6 subjects across 6 subject groups. Three are Higher Level (HL). 240 teaching hours over two years. Three are Standard Level (SL). 150 teaching hours. HL subjects go deeper, with more detailed content, more demanding assessment, and typically more challenging examination papers. Both SL and HL grades are scored 1-7, but HL grades carry more weight in many university admissions and HL is required for many degree programmes.
The workload difference
HL workload is meaningfully heavier than SL. typically 35-50% more contact time and homework. Three HL subjects plus three SL subjects plus core (TOK, EE, CAS) creates the standard IB Diploma workload. Adding additional HL subjects (occasionally permitted as 4 HLs) adds substantial additional work. Most students should not exceed 3 HLs.
The standard 3 HL choice
Most students take 3 HL + 3 SL. The HL choices typically include:
One language (English Language and Literature HL or Language B HL).
One science or mathematics (Biology HL, Chemistry HL, Physics HL, or Mathematics: Analysis and Approaches HL).
One humanities or arts (History HL, Economics HL, Business Management HL, Psychology HL, Visual Arts HL, etc.).
The exact mix should align with intended university degree pathway.
HL choices that match university degrees
Medicine: Chemistry HL is essential for most medical schools. Biology HL highly preferred. Mathematics SL or HL. Most medical schools prefer 3 sciences at HL plus Mathematics, but many accept Chemistry HL + Biology HL + one humanities HL.
Engineering: Mathematics: Analysis and Approaches HL essential. Physics HL strongly preferred. Chemistry or another science HL or SL.
Computer Science: Mathematics: Analysis and Approaches HL preferred. Computer Science HL or Physics HL useful.
Economics / Business: Mathematics: Analysis and Approaches SL or HL (HL preferred for top universities). Economics HL valuable but not always essential. Many top universities accept a wide range of HL combinations.
Law: Many universities flexible. English HL useful. History HL useful for top UK law programmes. Subject combination matters less than overall grades for most law programmes.
Architecture: Mathematics SL minimum, HL preferred. Visual Arts HL or Design Technology HL valuable. Physics HL useful for engineering-architecture overlap.
Liberal Arts: Most US liberal arts colleges flexible. Strong HL combination across diverse subjects works well. Less subject-specific requirement than UK/European universities.
Mathematics: Analysis and Approaches vs Applications and Interpretation
IB Mathematics splits into two distinct subjects:
Analysis and Approaches (AA): traditional pure mathematics with substantial calculus, algebra, statistics. Required for most STEM degrees, engineering, mathematics, physics, top economics. Available at SL and HL.
Applications and Interpretation (AI): applied mathematics with stronger focus on statistics, modelling, real-world applications. Suitable for liberal arts, social sciences, business management. Available at SL and HL.
Mathematics AA HL is required for most engineering and STEM degrees globally. Mathematics AA SL is acceptable for many business and economics programmes. Mathematics AI SL/HL is acceptable for liberal arts and many social sciences but not for STEM-heavy degrees. Worth choosing carefully. mathematics decisions are often locked in early in IB1.
The science HL question
Two science HLs is meaningful additional workload. particularly Biology HL plus Chemistry HL, both heavy in content. Three science HLs is exceptionally demanding and only suitable for highly capable students with clear medical or research career intentions. Most students take one science at HL and one at SL, or two sciences with one at SL.
Language B HL vs SL
Language B (second language) HL requires substantially stronger language proficiency than SL. For students with strong second-language background (heritage speaker, bilingual upbringing), Language B HL is achievable. For students learning language from scratch, SL is typically appropriate. Choosing Language B HL when language proficiency is weaker often produces poor grades. worth being realistic.
Group 6 (arts) considerations
Visual Arts, Music, Theatre, Dance and Film at HL deliver strong creative pathways but require substantial portfolio or performance work outside scheduled lessons. For students with strong creative interests aligned with university degree pathway (architecture, fine arts, performance arts), Group 6 HL is valuable. For students using IB as general academic pathway, Group 2 (second language) or Group 3 (humanities) at HL is often more flexible.
Switching between SL and HL
Most schools allow students to switch between SL and HL during early IB1. Switching from HL down to SL is generally easier than the reverse. By end of IB1, switches become difficult. By IB2, switches are usually impossible. Worth being thoughtful about initial selection. final commitment typically comes late IB1.
Predicted grades and HL/SL strategy
Universities make admissions decisions based on predicted grades from school plus actual exam results. Higher predicted HL grades carry more weight in admissions than higher predicted SL grades. Some students strategically choose subjects where strong performance is achievable rather than HL subjects where struggling for 6 vs 7 affects predicted grades and university outcomes. Worth discussing with university counsellor and subject teachers in IB1.