Cambridge advises Core for students expected to achieve grade D or below, and Extended for those expected to achieve C or above. Core caps at C. Extended Mathematics 0580 has no grade below E, while Extended sciences run down to G. Decide from full-paper mock data before the final entries deadline, 21 February in the 2026 June series.
What is the difference between IGCSE Core and Extended?
Core and Extended are different papers with different grade ranges. Extended covers the Core content plus the Supplement. The table shows the current syllabuses for the most-entered subjects.
| Syllabus | Core papers | Extended papers | Core grades | Extended grades |
|---|---|---|---|---|
| Mathematics 0580 | Papers 1 and 3 (1h 30m each, 80 marks each) | Papers 2 and 4 (2h each, 100 marks each) | C to G | A* to E |
| Biology 0610, Chemistry 0620, Physics 0625 | Papers 1 (multiple choice) and 3 (theory) | Papers 2 (multiple choice) and 4 (theory) | C to G | A* to G |
| All three sciences | Plus Paper 5 (practical test) or Paper 6 (alternative to practical), shared by both tiers | |||
| Co-ordinated Sciences 0654 | Papers 1 and 3 | Papers 2 and 4 | CC to GG | AA to GG |
| English as a Second Language 0510/0511 | Untiered | A* to G for all |
Sources: 0580 syllabus, 0610, 0620, 0625, 0654, 0511.
What does Cambridge say about choosing the tier?
Cambridge’s guidance is one sentence per tier. For 0580: “Candidates who have studied the Core subject content, or who are expected to achieve a grade D or below, should be entered for Paper 1 and Paper 3. These candidates will be eligible for grades C to G. Candidates who have studied the Extended subject content, and who are expected to achieve a grade C or above, should be entered for Paper 2 and Paper 4.” The science syllabuses use the same wording.
So the decision turns on one question: is this student expected to achieve C or above? Everything else is about how confident the school is in that expectation.
Why is the maths decision riskier than the sciences?
Because Extended Mathematics has no safety net below E. In the June 2026 0580 grade threshold table, the Extended paper combinations have no thresholds for F or G. Cambridge defines “ungraded” as performance that “did not meet the standard required for grade G”. An Extended maths student who falls short of E therefore risks leaving with nothing. The same student on Core would have had a grade C to G available.
In the sciences, Extended runs down to G, so a borderline Extended entry costs less if it goes wrong. So a borderline Extended entry is easier to justify in science than in maths.
How should schools make tier entry decisions with data?
Decide from full papers of the tier being considered, and put the borderline students in front of the whole department. A four-step method:
- Sit the real papers. The decisive mock should use a complete past series of the tier’s own papers, for example 0580 Papers 2 and 4, converted with that series’ thresholds. Our guide to setting grade boundaries for mock exams explains how.
- Sort into three groups. Secure Extended (comfortably above C), secure Core (clearly D or below), and borderline (within a few marks of the C threshold either way).
- Look behind the borderline grades. Question-level data shows whether a student is losing marks on Supplement-only content, which makes Extended risky, or on technique, which is fixable. See question-level analysis for mocks.
- Record the reason for every borderline decision, and tell the student and parents what the tier means for their possible grades before entries close.
When must tier decisions be final?
Before the final entries deadline, if the school wants to avoid late fees. For June 2026 the final entries deadline was 21 February and the late entries deadline 17 April. For November 2026 they were 16 August and 21 September (Cambridge key dates). The Cambridge Handbook 2026 says: “We charge late entry fees for any changes you make to entry options after the final entries deadline”, with a charge for each change. It adds: “We cannot change an entry once the candidate has taken the first component of an exam.” Because each tier has its own entry option, a school should expect tier changes after the deadline to attract these fees.
For June-series schools, that makes a January mock the natural decision point. The mock exam calendar shows the timing.
What about Edexcel International GCSE tiers?
Pearson tiers far fewer subjects: of its International GCSEs, only Mathematics A (4MA1) has Foundation (grades 5–1) and Higher (grades 9–4, with grade 3 allowed) entries. See our Edexcel International GCSE Foundation vs Higher guide. International GCSE Biology is untiered: its specification describes “untiered, written examinations with questions designed to be accessible to students of all abilities”. The same principle applies to Pearson’s tiered subjects: decide from the tier’s own papers.
How schools do this with AI Buddy
AI Buddy runs full-paper mocks for each tier and marks them instantly. Cohort analytics then show every student’s position against the C threshold and the topics costing them marks, including Supplement-only content. Heads of department can take a ranked borderline list, with evidence, into the entries meeting. The tier decision stays with the department.
Frequently asked questions
Should a student take IGCSE Core or Extended?
Cambridge advises Extended for students expected to achieve C or above, and Core for those expected to achieve D or below. Decide from a full mock on the tier’s own papers.
What grades can you get in IGCSE Core and Extended?
Core: C to G in Mathematics 0580 and the sciences. Extended: A* to E in Mathematics 0580, and A* to G in Biology, Chemistry and Physics.
Can you change from Extended to Core after entries close?
Changes after the final entries deadline attract late fees, and Cambridge cannot change an entry once the candidate has sat the first component.
Is IGCSE English as a Second Language tiered?
No. Cambridge removed tiering from English as a Second Language; all candidates take the same components and can achieve A* to G.
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Sources
- Cambridge International, Mathematics 0580 syllabus 2025–2027 and 0580 June 2026 grade threshold table
- Cambridge International, syllabuses for Biology 0610, Chemistry 0620, Physics 0625 and Co-ordinated Sciences 0654
- Cambridge International, Cambridge Handbook 2026, section 2.4
- Cambridge International, key dates for June 2026 and November 2026
- Pearson, International GCSE Biology specification