IB HL vs SL: Which Subjects Should You Take at Higher Level?

Picture two IB classmates who each earn a 6 in Chemistry. One takes it at Higher Level (HL), the other at Standard Level (SL). Both add six points to their score, which catches students off guard.

‍

HL and SL differ in depth, not value. HL adds about 90 teaching hours, more content, and usually a longer or extra exam paper. Yet both levels are graded 1 to 7 and count equally.

‍

In this guide, we’ll discuss what HL adds in each subject, how levels affect your diploma and college admissions, and how to choose your HL subjects.

‍

Let’s dig in.

Key takeaways

• HL runs about 240 recommended teaching hours against 150 at SL, adding Additional Higher Level (AHL) topics and usually an extra Paper 3 or longer exam papers.
• Both levels use the same 1 to 7 scale, so a 7 at HL and a 7 at SL each add seven points toward the 45-point maximum.
• To earn the diploma, you need at least 12 points across your HL subjects and 9 across your SL subjects, so one weak HL grade can block it even with 30 points overall.
• US colleges read your HL choices as depth in your intended major and often grant credit for HL scores of 5 or higher, while UK universities name required HL subjects and grades in their offers. 
• Choose HL where a target program, strong grade 9 and 10 results, and genuine interest overlap, such as Biology HL and Chemistry HL for pre-med students.
• A fourth HL is allowed but adds no points, and dropping from HL to SL is usually possible during Year 1 if you speak to your IB coordinator early.

What do HL and SL mean in the IB?

Most IB subjects run at two levels: HL adds depth and extra assessment, while SL keeps to the core foundation of each subject.

‍

Here’s how each level works in practice.

• Higher Level (HL) asks for about 240 recommended teaching hours, covering the full SL syllabus plus extra topics. Most students choose three HL subjects.
• Standard Level (SL) runs on about 150 recommended teaching hours, with grades on the same 1 to 7 scale as HL. Your other three subjects usually sit at this level.

IB HL vs SL: the key differences

The two levels differ in teaching time, content, exam papers, and internal assessment, yet both share the same grading scale. Here’s how the two levels compare at a glance.

‍

In the sections below, we’ll unpack the three main differences that shape your workload and score most directly.

Teaching hours and content

Over two years, HL’s 90 extra teaching hours add up to roughly one more semester of daily classes per subject.

‍

That time goes toward different work at each level.

• Higher Level (HL) spans about 240 teaching hours, adding Additional Higher Level (AHL) topics to the full SL syllabus. In Math: Analysis and Approaches (AA), that means complex numbers, proof by induction, and differential equations.
• Standard Level (SL) takes about 150 teaching hours and covers the same core topics without the AHL extensions. In Math AA SL, you study calculus and statistics but skip complex numbers and proof by induction.

Exams and internal assessments

Exam time is where HL and SL split most visibly, since HL usually adds either an extra paper or longer versions of the same papers.

‍

The pattern depends on the subject.

• Higher Level (HL) adds a Paper 3 in Math AA, Economics, and History, built around HL material. In Biology, Chemistry, and Physics, Paper 1 runs two hours and Paper 2 runs two and a half.
• Standard Level (SL) usually stops at two papers, so there’s no Paper 3 in those subjects. Science papers run 90 minutes each, and SL students complete about 40 hours of experimental work instead of 60.

Grading: why HL doesn’t earn extra points

HL subjects don’t earn extra points. A 7 at HL and a 7 at SL each add seven points to your total. Your six subjects contribute up to 42 points. Theory of Knowledge (TOK) and the Extended Essay add up to three more, for 45 in total.

‍

What does differ is the grade boundary, the minimum mark needed for each grade. The IB sets boundaries separately for HL and SL in each subject and exam session. In one session, for example, a 7 in Chemistry HL might need 70% of the marks. The same grade at SL might need 75%.

‍

Adding a fourth HL subject won’t raise your 45-point maximum either. HL counts in two other places: the diploma’s HL point minimum and the HL subjects colleges ask for. We cover both below.

What HL adds, subject by subject

What HL adds varies by subject, from new topics and longer writing tasks to a whole extra exam paper.

‍

These 10 subjects show the range.

How HL and SL affect your diploma score

Your HL and SL subjects each face their own minimum. You need at least 12 points across your HL subjects and 9 across your SL subjects. Both apply alongside the 24-point minimum.

‍

With four HL subjects, only your best three count toward the 12. With just two SL subjects, you need at least 5 SL points.

‍

A single weak HL grade can cost you the diploma. HL scores of 5, 4, and 2 total just 11. So, you miss the diploma even if SL grades of 7, 6, and 6 lift your total to 30.

‍

That risk grows because HL work runs alongside the TOK essay and exhibition, which our TOK guide explains.

Do colleges care whether you take HL or SL?

Yes, both US colleges and UK universities care. UK universities name required HL subjects and grades in their offers. In the US, HL signals depth in your intended major, judged against what your school offers.

‍

While HL and SL share one 1 to 7 scale, HL counts for more with colleges. It’s the closer match to AP and earns college credit more often, usually for scores of 5 or higher. Either way, check each college or university’s requirements before you choose.

‍

Which subjects should you take at Higher Level?

Your HL subjects belong where your goals, your grades, and your genuine interest in a subject all overlap.

‍

In the sections below, we’ll show when to choose HL or SL, with picks by career path.

Choose HL when…

Choose HL when a target college program expects the subject, your grades show strength, and you enjoy it. College fit comes first, so a future biology major gains more from Biology HL than History HL.

‍

Next, strong grade 9 and 10 results show you’re ready for the extra AHL content. Interest then carries you through all 240 hours of class. That interest also makes an HL subject a strong home for your Extended Essay, though the IB doesn’t require it. Our IB Extended Essay guide covers how to pick your subject. 

Choose SL when…

Choose SL for breadth subjects outside your major. A future history major, for instance, can take Chemistry at SL to cover the required science.

‍

Even at SL, chemistry can build the basics behind pigment analysis, which historians use to date artifacts. And SL carries the same 1 to 7 scale and weight as HL.

HL picks by career path

Your intended college major should shape your HL picks more than any ranking of difficulty, since admissions officers look for depth where you plan to specialize.

‍

These pairings fit five common paths.

• Medicine: Biology HL and Chemistry HL, since pre-med prerequisites center on both. Swap your arts subject for the second science.
• Engineering: Math AA HL and Physics HL cover the calculus and mechanics that first-year courses build on.
• Computer science: Math AA HL for proof-based reasoning, plus Computer Science HL or Physics HL.
• Economics: Economics HL with Math AA HL for calculus depth. Math AI HL also works for its statistics focus, but check your college’s requirements. 
• Law: English A: Literature HL and History HL build the close reading and argument law schools reward.

‍

If law is your goal, our guide on the classes you should take for law goes deeper into the high school subjects that build legal reasoning.

Should you take four HL subjects?

Four HL subjects are allowed, but few students need them. A fourth HL adds about 90 more teaching hours without raising your 45-point maximum. Only your best three HL grades count toward the 12-point minimum.

‍

Take a fourth HL only when a target program asks for it or your grades stay strong across all four. Otherwise, keeping that subject at SL protects your time and your total.

Can you switch between HL and SL?

Yes, though timing matters. Dropping from HL to SL is usually possible during Year 1, since the SL syllabus sits inside HL. Moving up from SL to HL is realistic only early in Year 1, before the AHL content gap grows.

‍

Either way, talk to your IB coordinator before exam registration closes. They can check whether the new class fits your timetable and what catch-up work you’d need.

Explore your HL subjects with Immerse Education

Most students pick HL subjects before studying any of them at college level. Grade 10 classes show your ability, but not always whether a subject will hold your interest for 240 hours.

‍

Immerse Education helps students aged 13 to 18 close that gap. At our Pre-University Summer School, you experience university-style study with expert tutors in medicine, law, or psychology.

‍

If you’d rather see a field at work, our Career Insights summer school brings industry visits and professional experience. And when travel isn’t an option, the Online Research pathway pairs you one-to-one with an expert academic from anywhere.

‍

Whichever you choose, you’ll pick your HLs with experience, plus evidence of interest admissions officers notice. Explore our pathways to find your fit.

FAQs

How many HL subjects do you need?

You need at least three HL subjects and can take up to four. Most students take three HL and three SL, and you must earn at least 12 points across your HL subjects.

Is HL harder than SL?

Yes, HL is more demanding than SL. It adds about 90 teaching hours, extra topics, and usually a longer or extra exam paper, so it suits subjects you’re strong in and enjoy.

Does HL give you extra points in the IB?

No, HL doesn’t give you extra points. A 7 at HL and a 7 at SL both add seven points, and your maximum score stays at 45 however many HLs you take.

What are the 5 hardest IB subjects?

Physics HL, Math AA HL, Chemistry HL, Biology HL, and English A: Literature HL are often named the most demanding. Demanding doesn’t mean you should avoid them, only that they need steady work.

Do colleges care if you take HL or SL?

Yes, colleges care because HL signals depth in your intended major. Admissions officers judge your choices against what your school offers, and UK universities often name required HL subjects in offers.

Is IB SL equivalent to AP?

No, IB SL isn’t a reliable AP equivalent. HL is the closer match, and many US colleges grant credit for HL scores of 5 or higher. SL credit is often limited and varies by college.

Conclusion: choosing your Higher Level subjects with confidence

Choosing your IB subjects comes down to fit, not prestige. Each HL should sit where your goals, grades, and interest overlap, while SL subjects protect your breadth and diploma minimums.

‍

Higher Level isn’t a badge of difficulty, since it earns no extra points. It’s a bet on depth where your future needs it most.

‍

Before placing that bet, our IB preparation blogs break down individual subjects, from syllabus content to exam strategy. Reading is a strong start, but firsthand experience tells you more.

‍

Immerse Education offers you that route, so you can test your subjects before committing 240 hours to them.