Exam season · 18 August 2026 · 6 min read
IGCSE physics grade boundaries, explained properly
Every August and January the same questions arrive on my WhatsApp: what percentage is an A*? Why did the boundary move? My mock says 82% — is that an A or an A*? Grade boundaries are simpler than the internet makes them look, and understanding them changes how you revise.
Who sets the boundaries, and when
Boundaries are not fixed in advance. After every session, the exam board looks at how the whole cohort performed and sets the thresholds so that a grade means the same standard from year to year. A hard paper gets lower boundaries; a gentle paper gets higher ones. This is why last session's thresholds are a guide, never a promise.
For Cambridge 0625 Extended, the syllabus aggregate combines Paper 2 (multiple choice, 30%), Paper 4 (theory, 50%) and Paper 5 or 6 (20%). Edexcel 4PH1 combines Paper 1 (110 marks, 61.1% of the qualification) and Paper 2 (70 marks, 38.9%). In both qualifications, the final grade comes from the overall result rather than one paper in isolation.
A concrete example: Cambridge June 2026
For Cambridge 0625 Extended in June 2026, the official A* threshold ranged from 156 to 165 out of 200 across the supported component combinations; A ranged from 133 to 140. Your exact papers matter, which is why the calculator on this site asks for the component combination.
The lesson is not to memorise those figures for a future series. It is to understand the size of your margin using the correct official table. Chasing one difficult question while easy definition, unit or graph marks go unclaimed is a poor trade.
The boundary region between A and A* is often decided by accumulated execution: units dropped, definitions paraphrased too loosely, explanations without a complete chain of reasoning, and practical-analysis marks missed. Knowledge and technique both matter.
A past boundary is a useful benchmark — never a promise for the next session.
What this means for your revision
Learn every definition precisely — definition questions offer repeatable marks when the required terms are present. Master the Paper 6 routines, because practical-analysis marks can accumulate quietly. And do past papers against the real mark scheme, so you know what a mark is actually paid for.
If you want to see where you stand right now, put your latest mock marks into the grade calculator on this site — it will tell you what the remaining papers need to deliver for each grade.