IB Diploma Explained — HL, SL, IA, TOK and the 45-Point Scale

What is the IB Diploma?

The International Baccalaureate Diploma Programme (IB DP) is a two-year pre-university qualification taken by students aged 16 to 19, typically as an alternative to A-Levels. IB World Schools offer it in over 160 countries, and universities worldwide accept it, including every UK university.

Where A-Level has you studying three subjects in depth, the IB Diploma has you studying six subjects simultaneously, plus three core components. That breadth is the biggest thing that sets IB apart, and also the biggest adjustment for students used to a narrower A-Level workload.

The six subject groups

IB students choose one subject from each of six groups:

1. Studies in Language and Literature — e.g. English A Literature, English A Language & Literature
2. Language Acquisition — a second language (e.g. French B, Spanish ab initio)
3. Individuals and Societies — e.g. History, Economics, Geography, Psychology
4. Sciences — e.g. Biology, Chemistry, Physics, Computer Science
5. Mathematics — Analysis and Approaches (AA) or Applications and Interpretation (AI), each at HL or SL
6. The Arts — e.g. Visual Arts, Music, Theatre. Students who don't want an arts subject can swap this for a second subject from groups 3 or 4.

Higher Level (HL) and Standard Level (SL)

This is one of the most important structural features of the IB. Each of your six subjects is taken at either Higher Level (HL) or Standard Level (SL). You must take exactly three HL subjects and three SL subjects.

• HL subjects cover more content, go into greater depth, and carry more teaching hours (240 hours over two years, vs 150 hours for SL). HL exams are longer and include questions that need greater analytical depth.
• SL subjects cover the core content of the syllabus at a less demanding level. They're still serious qualifications. SL grades contribute to your Diploma score and university applications just as HL grades do.

Choosing your HL subjects is one of the most important decisions you'll make when starting the IB. Pick subjects you're genuinely strong in and that fit your intended university course. Most universities specify which subjects they need at HL (a medicine applicant typically needs Biology and Chemistry at HL, for instance).

How each subject is graded

Every IB subject is graded on a scale of 1 to 7, where 7 is the highest. A grade of 4 is the minimum passing grade per subject. Your grade comes from a combination of:

• External assessment (EA) — exams sat in May or November of your second year, marked by IB examiners worldwide.
• Internal Assessment (IA) — coursework produced during the two-year course, assessed by your teacher and moderated externally by the IB. The IA is subject-specific: a Biology IA is a scientific investigation, a History IA is a historical investigation essay, an Economics IA is a portfolio of three commentaries.

The weighting between EA and IA varies by subject but usually sits around 75 to 80% external and 20 to 25% internal.

The three core components

On top of your six subjects, every IB Diploma student has to complete three core components:

Theory of Knowledge (TOK)

TOK is a compulsory philosophy-of-knowledge course. You explore questions like "How do we know what we know?" and "What counts as evidence across different disciplines?" TOK is assessed by an essay (1,600 words, submitted externally) and a class presentation. It's graded A to E and contributes bonus points to your Diploma total.

The Extended Essay (EE)

The Extended Essay is a 4,000-word independent research paper on a subject of your choice, usually one of your six IB subjects. A teacher at your school supervises it, and it's submitted externally. Like TOK, it's graded A to E.

Creativity, Activity, Service (CAS)

CAS asks you to engage in creative activities, physical activities, and service to others throughout your two years. There are no grades. CAS is pass/fail, but failing to complete it means you don't get the Diploma. Schools have varying requirements for what counts as CAS.

The 45-point scale: how your total is calculated

Component	Maximum points
Six subjects (max 7 points each)	42 points
TOK + Extended Essay bonus points	3 points
Total maximum	45 points

The bonus points from TOK and the EE are awarded on a combined matrix. Score A in both and you get 3 bonus points; A+B or B+A gives 2; lower combinations give 1 or 0. This makes the TOK essay and EE strategically important since they can add 3 points to your total without requiring any extra subject study.

The minimum score to be awarded the Diploma is 24 points, subject to meeting several other conditions:

• No grade below 3 in any HL subject
• No grade below 2 in any SL subject
• No grade of N (not submitted) in TOK, EE, or CAS
• No grade of E in TOK or EE
• Combined HL grades of at least 12 (e.g. 4+4+4)

How does IB compare to A-Level?

IB is broader, A-Level goes deeper. A student taking A-Level Chemistry spends more time on Chemistry than an IB HL Chemistry student does. For subjects where depth matters most at degree level, Mathematics and the Sciences especially, some university departments notice this and may offer bridging courses. For subjects where breadth and independent thinking matter more, Humanities and Social Sciences, IB students are often very well prepared.

UCAS points for IB: 45 points equals 720 UCAS tariff points; 38 points is roughly 600 UCAS tariff points. Most competitive universities don't actually use tariff points though, and look at the IB score and HL grades directly instead.

Revision for IB exams

IB exams are sat in a concentrated period in May (or November for southern hemisphere schools), which means you're revising six subjects at the same time. Prioritise your HL subjects since they demand more per subject and the questions are more demanding overall. ExamPass.ai supports IB subjects with practice questions and exam papers, including subject-specific question types matched to IB exam conventions.