Cambridge IGCSEs use A*-G. Edexcel International GCSEs use 9-1. The two scales are not identical, and parents read reports without knowing how they line up. Here is the clean version.
Quick answer: The IGCSE grading system uses two scales. Cambridge IGCSE is graded A* to G (with a 9 to 1 option in some regions), and Pearson Edexcel International GCSE is graded 9 to 1, with 9 the highest. Below the lowest grade is U (ungraded). Cambridge fixes three anchor points between the scales: grade 7 matches A, grade 4 matches C and grade 1 matches G. Schools and sixth forms usually treat C or 4 as a standard pass.
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IGCSEs are graded on two different scales depending on the exam board. Cambridge International (CAIE) uses the traditional A* to G scale. Pearson Edexcel International GCSE uses the 9 to 1 scale (the same scale used for UK national GCSEs since 2017). Both are valid, both are internationally recognised, and they are not directly equivalent on a one-to-one basis.
This guide explains exactly how each scale works, how they compare, what counts as a pass, and how to read your child's IGCSE report properly. For the wider context, start with our pillar guide on what IGCSE means (full form and basics). If you only need to know whether a result is good enough, read what counts as a good IGCSE grade. For board-specific tutoring, see Cambridge IGCSE or Edexcel IGCSE.
Cambridge International IGCSEs (CAIE) use the A*-G grade scale. From highest to lowest:
For Cambridge IGCSE, most universities and sixth forms treat C and above as a "good pass." Many subjects, particularly Mathematics, also separate into Core and Extended tiers — Core covers grades C to G, Extended covers grades A* to E. A student sitting Core cannot earn an A* or A; the higher grades are only available on the Extended paper.
Pearson Edexcel International GCSE uses the 9 to 1 scale, where 9 is highest and 1 is lowest. There is no 0 — below grade 1 is ungraded (U).
In Edexcel IGCSE, grade 4 is treated as a standard pass and grade 5 as a strong pass. Most UK universities and sixth forms set entry requirements at grade 5 (for example, "grade 5 in English and Maths") rather than the older grade 4 floor.
Like Cambridge, Edexcel offers tiered papers in some subjects — Foundation (grades 5-1) and Higher (grades 9-3). The top grades 9, 8 and 7 are only available on the Higher tier.
Cambridge International has published how its two scales line up. The standards at the thresholds of grades 7, 4 and 1 are the same as the thresholds of grades A, C and G. The other 9 to 1 boundaries are spaced at regular intervals between those anchors (Cambridge: how 9-1 grading works). That gives this chart:
| 9–1 grade | A*–G grade | How it lines up |
|---|---|---|
| 9 | A* (top end) | Above the A* standard, the hardest grade to reach |
| 8 | A* | Roughly A* level |
| 7 | A | Anchor: the grade 7 threshold equals the grade A threshold |
| 6 | B | Roughly B level |
| 5 | B / C | Between B and C, often called a strong pass |
| 4 | C | Anchor: the grade 4 threshold equals the grade C threshold |
| 3 | D / E | Below a standard pass |
| 2 | E / F | — |
| 1 | G | Anchor: the grade 1 threshold equals the grade G threshold |
Only the three anchor rows are exact. The others are approximate, because the two scales have a different number of grades. The 9 to 1 scale also spreads out the top end: where A*–G has only A* at the top, 9–1 separates very strong candidates into 7, 8 and 9. This is one of the genuine differences between the two boards and is covered in our is Cambridge or Edexcel IGCSE harder guide. For Edexcel's own 9 to 1 papers and tiers, see the Edexcel IGCSE 9-1 guide.
Parents often ask what percentage an A* or a 9 is. There is no fixed answer, and neither board publishes a permanent percentage scale. After every exam session, Cambridge and Pearson set grade thresholds (Cambridge's term) or grade boundaries (Pearson's term): the minimum raw mark needed for each grade on that particular paper. A harder paper gets lower boundaries, an easier one gets higher boundaries.
So the same percentage can be an A* in one session and an A in the next. To turn a past-paper score into a grade, always use the official threshold table for that exact syllabus, session and paper combination:
Tiered subjects add one more layer: a Core or Foundation paper has its own, lower set of boundaries, and its top grade is capped.
In Cambridge subjects with two tiers, Core covers grades C to G and Extended covers A* to E, so a Core candidate cannot get above a C (Cambridge help centre). In Pearson Edexcel tiered subjects such as Maths, Foundation covers grades 5 to 1 and Higher covers 9 to 4, with an allowed grade 3. Choosing the tier is a real decision with real consequences: see our guide to Core vs Extended IGCSE.
For sixth-form (A-Level) and IB Diploma entry at competitive schools, students typically need:
For selective university courses in the UK, US, Canada and Australia, admissions tutors look beyond the standard pass: they want to see a profile loaded with 7-9s (A and A*) and especially in the academic subjects. We cover the implications in our IGCSE subjects for medicine guide and best IGCSE subject combinations.
Both Cambridge and Edexcel publish grade boundaries after each exam session. Boundaries are not fixed in advance — they are set retrospectively based on the difficulty of that particular paper and the overall performance of the cohort. This is why a 90% raw score might be an A* one year and an A the next; the absolute number of marks for each grade can move.
The principle is "comparable outcomes": the proportion of candidates achieving each top grade is broadly stable year to year. So if a paper is harder, the boundary falls. If it is easier, the boundary rises. This means past-paper raw scores are useful as a benchmark, but parents should look at the grade rather than the percentage when judging progress.
If a result lands just below a boundary, our guide to IGCSE remarks and Oct/Nov results day explains how a review of marking works and when it is worth asking for one.
Our 1-on-1 IGCSE tutors specialise in Cambridge CAIE and Edexcel separately — each board has its own paper structure, mark scheme style, and tiered entries. Free diagnostic trial assesses current grade band and maps out the route to A*/9.
💬 Book a Free Trial on WhatsAppOfficial sources: Cambridge IGCSE grading · Pearson Edexcel International GCSE.
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For board-specific IGCSE tutoring, see Cambridge IGCSE or Edexcel IGCSE. Subject pages: IGCSE Maths, IGCSE Physics, IGCSE Chemistry, IGCSE Biology, IGCSE English.
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