Your IGCSE mock results are the single best indicator of where you’ll end up in the real exam — but only if you interpret them correctly. This guide explains how to convert your raw mock marks into a realistic grade estimate, what confidence to place in that estimate, and how to use it to direct your remaining revision time.

Why Mock Marks Don’t Directly Equal Final Grades

Two important factors mean your mock mark and your predicted grade aren’t a simple read-across:

1. Grade boundaries shift every year. Cambridge sets boundaries after marking — not before. A mark of 140/200 in Biology might be a B in one year and an A in another, depending on how difficult the paper was.

2. Mocks use different papers from the real exam. Schools often use past papers for mocks. If your mock used a 2022 paper, the boundary that applied to those questions was the 2022 boundary — not necessarily the 2026 one.

This is why using historical average boundaries gives a better estimate than any single year’s data.

Step-by-Step: Estimating Your IGCSE Grade

Step 1: Add up your raw marks across all papers

For most IGCSE subjects, add your marks from each paper into a single total:

• Cambridge IGCSE Biology (0610): Papers 1 + 2/3 + 5/6 = total out of 200
• Cambridge IGCSE Chemistry (0620): Papers 1 + 3 + 5/6 = total out of 200
• Cambridge IGCSE Physics (0625): Papers 1 + 3 + 5/6 = total out of 200
• Cambridge IGCSE Mathematics (0580): Papers 2 + 4 = total out of 280

If you’ve only sat some papers, scale proportionally: if you sat 2 out of 3 papers worth 160/200 total marks, your scaled score = (your mark ÷ 160) × 200.

Step 2: Compare against historical average boundaries

Use these approximate historical averages (Cambridge IGCSE, May/June series) as your guide:

Subject	A* boundary	A	B	C
Biology 0610 (out of 200)	~160	~132	~105	~78
Chemistry 0620 (out of 200)	~163	~135	~107	~80
Physics 0625 (out of 200)	~159	~132	~106	~80
Maths 0580 (out of 280)	~213	~180	~148	~115

These are averages — in any given year they may be 5–10 marks higher or lower.

Step 3: Understand the confidence range

Your predicted grade comes with uncertainty based on year-to-year boundary variation (typically ±8–12 marks):

• If your mark is 15+ above the average A* boundary → Likely A* (comfortable margin)
• If your mark is 5–15 above the boundary → Possible A* (borderline — could go either way)
• If your mark is within 5 marks below the boundary → Borderline — very close, could land either side

Step 4: Use a tool for automatic calculation

Rather than doing this manually, use the Grade Predictor — enter your marks per paper, select your subject, and get an instant predicted grade with a confidence level (Likely / Possible / Borderline). It also shows you exactly how many more marks you need for the next grade up.

Estimate your IGCSE grade →

What If You’re Borderline?

Being within 10 marks of a grade boundary with 4–6 weeks to go is actually an excellent position — a focused push on two or three topics can be enough to move you up.

Where those marks typically come from:

Exam technique, not content. Most borderline students know the content but lose marks writing answers that don’t match the mark scheme. “The enzyme stops working” loses the mark; “the active site changes shape (denatures) so the substrate can no longer bind” earns it. Improving how you write answers is the fastest route to extra marks.

Targeted topic revision. Identify the 2–3 topics where you drop the most marks. Practise those specifically — not a full paper, but past paper questions on those topics only.

The practical paper. Biology, Chemistry and Physics all include Paper 5/6 worth 40 marks (20% of total). Many students underrevise this paper. It tests skills you can practise: graph drawing, identifying errors, designing experiments.

Tools to Support Your Estimate

Grade Predictor — enter your mock marks across multiple papers, get a predicted grade with confidence level and marks-to-next-grade

Grade Boundary Tracker — look up year-by-year Cambridge boundaries for your subject

Revision Priority Planner — once you know which grade band you’re in, use this to rank topics by weakness and days remaining

Mark Scheme Decoder — practise writing answers exactly the way Cambridge marks them

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