How IGCSE grade boundaries work, and why they change each series

The headline finding

A grade boundary is the lowest total that earns a grade. Cambridge calls it a grade threshold. It is not fixed in advance. Cambridge sets new boundaries for every paper in every series.

Cambridge says it sets them using a mixture of statistical evidence and expert judgement. Its stated aim is to maintain standards from year to year, so that a student who performs the same way gets the same grade whenever they sit the exam.

Every series has new papers, and papers differ. So the marks needed for a grade can differ too, from one series to the next and from one variant to another.

The data: three June series of Physics 0625

Cambridge does not add up raw marks directly. Each paper is multiplied by a weighting factor first. For 0625 Extended, the factors are 1.5 for Paper 2, 1.25 for Paper 4 and 1 for Paper 6.

That turns 40 + 80 + 40 raw marks into 60 + 100 + 40 = 200. Paper 2 then carries 30% of the total, Paper 4 50% and Paper 6 20%, the weightings in the syllabus.

The table below follows one route through three June series: Papers 21, 41 and 61 (Extended, first variant, with the Alternative to Practical). Cambridge lists this route as option CX in 2023 and 2024.

Minimum weighted total out of 200 for components 21, 41 and 61. Sources: Cambridge IGCSE Physics 0625 grade threshold tables for June 2023, June 2024 and June 2026, cambridgeinternational.org. The weighting factors follow from the 200-mark total; the 30/50/20 split is from the 0625 syllabus for 2026 to 2028. Percentages are our own arithmetic.

Across these three series, every boundary rose. The A* boundary went up by 35 marks and the C boundary by 28. At grade A, Paper 4 moved most: from 37 to 53 out of 80 between 2023 and 2026.

Variants differ too, even within one series. Cambridge generally writes three variants of each paper, for exam security. Each is sat by schools in different administrative zones.

Minimum weighted total out of 200. Source: Cambridge IGCSE Physics 0625 grade threshold table, June 2023.

In June 2023 the C boundary was 22 marks apart between two variants of the same exam. In June 2024 the gap was smaller, at 7 marks (74 against 81).

What it means for your revision

The numbers change, but the lessons for revision are stable.

1. 1

   Aim at a standard, not a number

   No one knows your boundary until results day. Aim well above recent A boundaries rather than at a single figure.

   Tip. The highest A boundary in our table is 70% of the weighted total. Practise until you score comfortably above that.
2. 2

   Match the table to the paper

   When you mark a past paper, use the threshold table for that exact series and variant. Boundaries from another series or variant tell you little about the paper in front of you.

3. 3

   Weight your marks before you compare

   Multiply each paper’s raw mark by its factor, then add. Comparing raw totals with a weighted boundary will mislead you.

4. 4

   Know where the weight is

   Paper 4 carries half of the 0625 Extended total, so it rewards the most revision time.

   Tip. Per raw mark, Paper 2 counts most: each multiple-choice answer is worth 1.5 weighted marks.

Here is the conversion for one set of raw marks, graded against each of the three tables.

An invented candidate. 143 is an A* against the June 2023 table, and an A against June 2024 and June 2026.

The same raw marks give different grades because each series has its own papers and its own thresholds. That is why a mock grade from an old table is a guide, not a forecast.

Caveats

Where to go next