Wondering what mark you actually need for a Grade 7 — or an A? IGCSE grading isn't a fixed percentage scale — it's built from grade boundaries, weighted components, and sometimes tiering or a Uniform Mark Scale. This guide breaks the whole system down, walks through a full worked example, and shows you how to estimate your grade before results day without falling for the common mistakes that throw students off.

The short version: Convert each paper's raw mark into a weighted contribution, add them into one overall percentage, then compare that percentage against the published grade boundaries for your subject and exam series — never against a generic "90% = Grade 9" scale.

IGCSE Grades Aren't Fixed Percentages

A common myth is "90% = Grade 9." In reality, exam boards set grade boundaries — the minimum raw mark needed per grade — after marking each exam series, based on how the whole cohort performed and how difficult that particular paper turned out to be.

Surprising, but true: it's the opposite of what many people assume — Cambridge is the board still using letters (A*–G), while Edexcel is the one mostly using numbers (9–1).

Because boundaries move with each exam series, the same raw mark can be a Grade 8 one year and a Grade 7 the next.

Step 1: Know Your Raw Marks

Every paper has a maximum raw mark. Before estimating anything, you need your actual mark on each individual component — not a rounded-off percentage, but the exact number the examiner would write on the script.

If you only have a percentage from a mock, convert it back first:

Raw mark = (percentage ÷ 100) × total marks available

Step 2: Apply Component Weightings

Most IGCSE subjects combine several components — written papers, coursework, practicals — each contributing a different percentage to your final grade. The formula:

Weighted contribution = (marks scored ÷ total marks) × paper weighting

Work through this for every component, then add the results together. The total is your overall weighted percentage for the subject.

Step 3: Check for Tiering

Sciences and Maths are often tiered:

Watch out: entering the wrong tier caps your maximum possible grade regardless of raw performance. Confirm your tier with your teacher before estimating anything — and make sure you're comparing against that tier's boundary table, not the other one's.

Step 4: Understand Raw Marks vs. UMS (Edexcel Only)

This is where a lot of students get confused, especially with Edexcel. Cambridge IGCSE grades entirely from raw marks converted straight to a percentage uniform mark (PUM) and then a letter grade — there's no separate UMS layer. Edexcel is different depending on the qualification:

If you're not sure which applies to your subject, check your specification code — modular subjects will explicitly mention "unit" results and UMS conversion tables.

Worked Example: Calculating a Full Subject Grade

Here's how it looks in practice for a student sitting Cambridge IGCSE Combined Science (Extended):

Component Marks Scored Total Marks Weighting Weighted Contribution
Paper 2 (Theory) 62 80 40% 31.0%
Paper 4 (Theory) 54 70 35% 27.0%
Paper 6 (Practical) 40 50 25% 20.0%
Total — — 100% 78.0%

Reading the result

Add the weighted contributions together to get an overall percentage — 78.0% here — then compare it against that subject's published grade boundaries for the relevant exam series (not a generic percentage scale). If last year's Grade A boundary for this subject sat at 76%, this student would be comfortably inside an A grade, with a small buffer above the line.

Note: Paper 2 alone contributed 31.0% of the final grade — more than Paper 6's entire 25% weighting. That's why weighting before comparing to boundaries matters so much.

Cambridge vs. Edexcel: Key Differences at a Glance

  Cambridge IGCSE (CIE) Edexcel (Pearson) IGCSE
Grading scale A*–G (with U), kept deliberately instead of moving to 9–1 9–1 for most subjects (with U)
Uses UMS? No — raw marks only Only for modular qualifications
Boundaries published After each series, per component After each series, per component (and per UMS band where relevant)
Tiering Common in Sciences/Maths Also present, structured similarly

The underlying logic — raw marks, weighting, boundaries — is the same for both boards. The main practical differences are the grading scale itself and Edexcel's occasional UMS layer.

Common Mistakes When Estimating Your Grade

The Faster Way: An IGCSE Grade Calculator

Manually weighting components across several subjects — and getting the tier and mark scale right each time — is slow and easy to get wrong. IGCSE Grade Calculator does this for you: enter your raw marks per component, and it estimates your grade using recent boundary data across Cambridge, Edexcel, and other IGCSE-style boards. Useful for:

Try It Yourself

Stop guessing and estimate your grade with real weighting math — free, no sign-up required.

Open the IGCSE Grade Calculator →

Frequently Asked Questions

Is IGCSE Grade 9 the same as an A*?

Broadly, Edexcel's Grade 9 sits above the old A* to distinguish the very top performers, though it isn't a strict one-to-one swap. Note this comparison mainly applies to Edexcel — Cambridge IGCSE still awards A* directly for most subjects rather than a 9.

Do IGCSE grade boundaries change every year?

Yes, they're recalculated each exam series so grading stays fair across papers of varying difficulty.

Can I know my exact grade before results day?

Not officially — boundaries stay confidential until results are released. You can only produce a close estimate from past boundaries.

Does coursework affect my IGCSE grade?

For subjects with a coursework or practical component, yes — it's weighted alongside written papers per that subject's syllabus.

What's the difference between a raw mark and a UMS mark?

A raw mark is the actual score an examiner gives you on a paper. UMS is a converted, standardised score Edexcel uses for some modular qualifications so results from different sessions can be combined fairly — Cambridge IGCSE doesn't use UMS at all.

Why did my predicted grade differ from my actual result?

Small prediction errors are common and usually reflect natural variation in how boundaries are finally set, not necessarily a miscalculation on your part — treat any estimate as a close range rather than a certainty.

Can I use last year's grade boundaries to predict this year's grade?

You can use them as a reasonable guide, but not a guarantee — boundaries are reset each series based on that year's paper difficulty and cohort performance.

Grade boundaries, weightings and tiering rules are set by the examination board for each subject and exam series, and can change. Always confirm the current syllabus, weighting structure and published boundaries directly with Cambridge International, Pearson Edexcel or your exam centre. This page is an educational summary based on publicly available guidance as of 2026 and is not an official grading service.

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About the Developer

I am Chew, an education technology developer and academic consultant with 5+ years building educational websites. I developed the IGCSE Grade Calculator to bridge the gap between complex official PDF thresholds and student accessibility.

The mathematical models used in this calculator are verified against the Cambridge Assessment International Education (CAIE) guidelines for component weighting. This ensures that the "Total Weighted Mark" produced here matches the logic used by official examiners.