TOK and CAS in IB: Bonus Points, Rules and Requirements

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What is TOK in the IB Diploma?

Theory of Knowledge (TOK) is one of the three IB Diploma core elements. It is a course about how we know what we know — exploring knowledge questions across the disciplines (history, sciences, arts, mathematics, human sciences). TOK is assessed by a 1,600-word essay (two thirds of the grade) and an exhibition with three real-world objects (one third), graded A to E. The TOK grade combines with the Extended Essay grade for up to 3 bonus IB points.

The IB Diploma has six subjects plus a "core" of three required components: Theory of Knowledge (TOK), the Extended Essay (EE), and Creativity, Activity, Service (CAS). TOK and EE together contribute up to 3 bonus points to the IB total via a published matrix. CAS does not contribute points but must be completed for the Diploma to be awarded.

This guide covers TOK and CAS in detail. For the Extended Essay see our separate guide on how to write an A-grade Extended Essay. For the wider Diploma structure: what the IB Diploma is.

Theory of Knowledge (TOK) — The Course

TOK is a course about how we know what we know. Students explore knowledge questions across the disciplines — what counts as evidence in history, what makes a scientific claim "true," how arts produce knowledge that other forms cannot. It is taught across both IB Diploma years (roughly 100 hours total) and aims to develop critical thinking and reflective awareness.

The course is organised around two key questions:

• How is knowledge produced?
• What is the value and limits of that knowledge?

And around themes (knowledge and the knower, plus optional themes like knowledge and technology, language, politics, religion, indigenous societies) and areas of knowledge (history, the natural sciences, the human sciences, mathematics, the arts).

TOK Assessment — The Essay and the Exhibition

TOK is assessed by two pieces:

• The TOK Essay (two thirds of the TOK grade) — a 1,600-word essay on one of six prescribed titles released by the IB each year. The essay is externally marked. It is the higher-stakes piece.
• The TOK Exhibition (one third of the TOK grade) — students choose three real-world objects that respond to one of 35 IA prompts (e.g., "What features of knowledge have an impact on its reliability?"). Each object is commented on in around 950 words total. The exhibition is internally marked by the school and moderated by the IB.

TOK is graded on a five-letter scale: A (highest), B, C, D, E (lowest). The grade combines with the Extended Essay grade via a published matrix to award 0-3 bonus points to the IB total.

How many points is TOK worth? The TOK and EE matrix

TOK on its own earns no points. The IB combines your TOK grade with your Extended Essay grade in this published matrix to award 0 to 3 core points:

Two things stand out. First, an E in either TOK or the EE is a failing condition, so the Diploma is not awarded however high the total. Second, a D does not fail on its own but drags the points down. Aim for at least B in both: B/B earns 2 points, and A/B or B/A earns the full 3. For how the core points sit inside the 45, see how the IB is scored and what counts as a good IB score. For the essay side, read our Extended Essay guide.

Creativity, Activity, Service (CAS) — What It Is

CAS is the experiential learning component of the IB Diploma. Students engage in a portfolio of activities across three strands across the two IB years:

• Creativity: arts, performance, creative thinking, devising and producing original work.
• Activity: physical exertion contributing to a healthy lifestyle.
• Service: voluntary work that benefits a community, undertaken with thoughtful reflection.
• CAS Project — at least one collaborative, substantive project of one month or more that ideally combines all three strands.

There is no minimum hour count globally, though many schools impose their own guidelines (50 hours per strand was a historical guideline; the IB has formally removed the hour requirement and replaced it with quality-and-evidence-based assessment).

Is CAS graded?

No. CAS is not graded and earns no points. It is either completed satisfactorily or it is not, and an incomplete CAS means the Diploma is not awarded. That makes it a requirement to plan for steadily across both years, not an afterthought.

CAS Assessment and Completion

CAS is assessed pass/fail. There is no grade. The IB requires evidence that students have:

• Engaged with all three strands (creativity, activity, service) over the two years.
• Completed at least one CAS project of one month or more.
• Achieved the seven CAS learning outcomes (identifying strengths and areas for growth, demonstrating challenge, planning and initiating, working collaboratively, demonstrating commitment, engaging with global significance, recognising ethical implications).
• Documented their engagement in a CAS portfolio (digital or physical) with reflective entries linking activities to learning outcomes.

Students who do not satisfactorily complete CAS do not receive the Diploma, even if their subject grades and TOK/EE are strong. The CAS coordinator at the school determines satisfactory completion based on the evidence in the portfolio.

Time Investment and Strategy

Honest time guidance over the two IB Diploma years:

• TOK — roughly 100 hours of class time plus 30-50 hours for the essay and exhibition. Treat the essay as a serious 4-6 week project, not a one-week scramble.
• CAS — variable; most students average 2-4 hours per week across the two years on activities and reflections. The portfolio reflections are the most commonly under-prepared element.
• EE — see our Extended Essay guide; roughly 40 hours of work spread over 6-9 months from planning to final draft.

The students who score the most bonus points start TOK and EE early in IB Year 1 and keep the CAS portfolio current rather than scrambling in IB Year 2.

Continue: IB Extended Essay help, what the IB Diploma is, what is a good IB score, HL and SL in IB. Extended Essay subject guides: Economics, Psychology, History and Physics.

Official sources: IB Diploma (official), Theory of knowledge (official), IB Diploma passing criteria.

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