The IB core requirements — Theory of Knowledge, the Extended Essay, and CAS — are what genuinely distinguish the Diploma Programme from a simple collection of six subjects, and understanding what each involves, how they’re assessed, and how they interact with each other early makes planning your two years significantly easier.
Theory of Knowledge (TOK), in Detail
TOK asks a fundamentally different kind of question than your other subjects: not “what do we know,” but “how do we know it, and how confident can we genuinely be.” It’s assessed through two components — the TOK Exhibition, where you connect three real-world objects to one of a set of prescribed titles, and the TOK Essay, a longer analytical response to a different prescribed title released for your specific exam session. Both components are graded on a letter scale from A to E, rather than the numeric 1-7 scale used for your six subjects. See our full guide on what TOK is and why it confuses so many students if the underlying concept still feels unclear at this stage.
The Extended Essay (EE), in Detail
The Extended Essay is a 4,000-word independent research paper on a topic of your own choosing, connected to one of your six DP subjects — genuinely the closest thing the IB offers to a university-style, self-directed research project. It’s assessed against five specific criteria, with Critical Thinking carrying the most weight, meaning genuine analysis and evaluation matter considerably more than simply demonstrating subject knowledge or thorough research alone.
CAS (Creativity, Activity, Service), in Detail
CAS asks you to engage in sustained activities outside the traditional classroom across three strands — Creativity, Activity, and Service — over roughly 18 months of the programme. Since 2017, this is assessed through evidenced reflection tied to seven specific learning outcomes rather than a fixed hour count, a meaningful change from how CAS used to work (see our guide on how many CAS hours you actually need for exactly what changed and why).
How the Core Contributes to Your Final Diploma Score
TOK and the Extended Essay combine through a published bonus matrix to contribute up to 3 additional points toward your overall 45-point Diploma total, on top of the 42 points available from your six subjects — see our full breakdown of how the IB Diploma points score is calculated for the complete mechanics, including a worked example. CAS doesn’t contribute numeric points directly, but it must be satisfactorily completed for the full Diploma to be awarded at all, regardless of how strong your subject grades are.
Why the Core Matters Beyond Just the Score It Contributes
Beyond their direct scoring impact, the core components are frequently what universities specifically cite as evidence of independent thinking, sustained commitment, and genuine engagement beyond pure academic performance — material genuinely worth using well in a personal statement or application essay, rather than treating as separate obligations disconnected from your broader application story.
How the Three Components Typically Interact Across Your Two Years
While each is assessed separately, strong students often find natural connections between them — a CAS experience that informs a TOK real-life situation, or an Extended Essay topic that grew out of a subject you’re also exploring through TOK’s lens. These connections aren’t required, but noticing and developing them tends to produce more genuinely engaged, coherent work across all three components rather than treating each as an isolated obligation.
Final Tip
Start thinking about all three core components early in Year 12, even informally — a TOK idea that genuinely sticks with you, a research question forming in the back of your mind, a CAS activity you’re authentically drawn to. The strongest core work across all three components usually starts from genuine curiosity discovered with time to develop, not a rushed decision made close to a deadline.