Every IB student takes three subjects at Higher Level and three at Standard Level. The decision affects university entry, workload, and exam performance across two years. Here is how to get it right.
This guide explains the real difference between IB Higher Level (HL) and Standard Level (SL) — including how universities use HL grades, what each level requires in terms of content and assessment, and how to choose which three subjects to take at HL. Whether your child is at an IB school in the UAE, Singapore, UK, or Malaysia, this decision has direct consequences for university offers. For 1-on-1 IB Diploma tutoring at both HL and SL, we cover every subject.
The IB Diploma requires every student to study six subjects: three at Higher Level (HL) and three at Standard Level (SL). That structure is fixed. What is not fixed is which subjects go where — and that decision shapes the next two years more than most students realise when they make it.
Choose the wrong subjects at HL and the workload becomes unmanageable, university requirements go unmet, or grades in the most important subjects suffer. Choose well and the combination plays to the student's strengths, satisfies university prerequisites, and distributes the workload sensibly across two years.
Here is a clear, practical guide to the difference and how to choose.
HL and SL are not just different amounts of the same thing. They are different courses. The content covered at HL is broader and goes significantly deeper. The exam papers are longer. The Internal Assessment requirements are more demanding. And the assessment criteria at HL expect a higher level of analytical sophistication than SL.
The practical implication: a student who takes Chemistry at SL and a student who takes Chemistry at HL are not sitting the same exam. The HL student covers organic chemistry topics, reaction mechanisms, and quantitative work that the SL student does not. If that student then applies to study Medicine, which requires A-Level or IB HL Chemistry, the SL preparation is insufficient — not because the student did not work hard, but because the content was different.
IB HL (Higher Level) covers additional topics, has longer exam papers, and requires greater analytical depth than SL. HL has 240 teaching hours vs 150 for SL. University conditional offers frequently specify minimum grades in HL subjects — a student cannot meet an HL requirement with an SL grade, regardless of their overall points total.
This is the most consequential aspect of the HL vs SL decision, and the one that is most often underestimated when students are choosing in Year 11 or early DP1.
Competitive universities — UK Russell Group, US top universities, NUS, NTU, and others — frequently specify minimum grades in specific HL subjects as part of their conditional offer. A typical offer for Medicine at a UK medical school might read: "38 points overall with 7,6,6 at HL including Biology and Chemistry." That offer cannot be met with Biology and Chemistry at SL, regardless of the overall points total.
| Degree Programme | Typical HL Requirement | Notes |
|---|---|---|
| Medicine (UK) | Biology HL + Chemistry HL | Both compulsory at HL — SL not accepted |
| Engineering | Mathematics AA HL + Physics HL | Some accept Chemistry HL instead of Physics |
| Economics (competitive) | Mathematics AA HL or Economics HL | Check individual university requirements |
| Law | Usually flexible on HL subjects | Strong overall points and English HL often preferred |
| Computer Science | Mathematics AA HL | Computer Science HL also valued |
| Psychology | Often flexible — Psychology HL preferred | Biology HL sometimes requested |
| Business (competitive) | Mathematics HL or Economics HL | More quantitative programmes increasingly specify Maths HL |
The rule that matters most: Check the specific HL requirements for the universities and programmes your child is targeting before finalising the subject combination. Do this in Year 11 or early DP1 — not in DP2 when the courses are already fixed and the exams are approaching.
Three principles guide this decision. Apply them in order.
Identify the degree programmes your child is most likely to pursue — or the broad field if specific programmes are undecided. Find out which HL subjects those programmes typically require. Those subjects go to HL. This is non-negotiable. A student who puts Biology at SL and later decides to apply to Medicine is in a very difficult position.
Of the remaining HL slots, fill them with subjects where your child has genuine ability. HL is 240 teaching hours of content that goes meaningfully deeper than SL. A subject at HL needs to be one the student can perform in under sustained pressure over two years. A student who is strong in History and weak in Physics should not take Physics HL to impress — they should take History HL and perform in it.
Three highly demanding HL subjects simultaneously is more manageable for some students than others. Three essay-heavy HLs — English, History, Economics — produces a very different workload from two sciences and one essay subject at HL. Consider what the combined preparation looks like across two years, not just what looks good on a course selection form.
Yes. Physics HL, Chemistry HL, and Biology HL can be taken simultaneously. Many students targeting competitive medicine programmes choose this combination. It is demanding — three experimental sciences at HL involve three separate IAs alongside the content and exam pressure. Students who choose this route typically have a very strong science background from IGCSE and need to manage the IA timelines carefully across DP1 and DP2. For guidance on preparing for IB science subjects, our IB Diploma tutoring page covers all three at HL and SL.
IB HL and A-Level cover broadly similar content in most subjects, but they assess differently. IB HL uses criteria-based marking across all components; A-Levels use mark schemes, either point-based or levels-based. Many universities treat an IB HL grade 7 as broadly equivalent to an A-Level A*. The content depth at A-Level tends to go further in specific subjects — Cambridge A-Level Physics, for example, covers more content than IB Physics HL — but IB HL includes Internal Assessment which A-Levels largely do not.
The IB Diploma requires a minimum of 12 points across the three HL subjects combined, and no grade below 2 in any subject. A student who scores a 1 in an HL subject does not receive the Diploma regardless of their overall points total. A student who scores below the minimum conditional offer grade in an HL subject (e.g., a 5 when the offer required a 6) may find the university place is withdrawn. These are the high-stakes consequences that make HL subject choice so consequential.
For more on IB Diploma preparation, see our posts on IB Diploma vs A-Levels, IB Maths AA vs AI, how to score a 7 in IB Economics, and how to write an IB Extended Essay.
We offer 1-on-1 IB Diploma tutoring for every subject at both HL and SL. If your child is choosing their combination, we can advise. If they are already in DP1 or DP2 and need support, we build the preparation around the exact level and paper they are sitting. Free diagnostic trial — no commitment required.
💬 Book a Free Trial on WhatsAppPut at HL: the subjects your university pathway requires, plus the subjects where your child performs best. Put at SL: the subjects that round out the group requirements but are not central to the degree aspiration.
Then prepare each HL subject as if the grade in it is the grade that determines the university offer. Because for many students, it is exactly that.
IB HL and A-Level are broadly comparable in difficulty, but assess differently. IB HL uses criteria-based marking and includes Internal Assessment; A-Levels use mark schemes and are primarily exam-based. A-Level content in many subjects (particularly sciences and mathematics) goes further in depth than the equivalent IB HL. Many universities treat IB HL 7 as equivalent to A-Level A*.
The IB Diploma structure requires exactly three HL subjects — no more, no fewer. The choice of which three should be based on university pathway requirements first, then personal strength, then workload balance. Students cannot choose to take four HL subjects under the standard Diploma structure.
Changing from HL to SL after the start of DP1 is possible in most schools but requires approval. It is less disruptive early in DP1 and increasingly difficult as IA deadlines approach in DP2. The earlier a level change is identified as necessary, the smoother the transition. A tutor can help identify whether a change is needed based on performance trajectory.