IGCSE grade to percentage

"What percentage is a 9?" "Is a 7 always 70%?" These are the most-asked IGCSE grading questions, and the honest answer surprises people: there is no fixed percentage for any grade. Here's why, and how to work out the real figure for your subject instead of trusting a made-up rule of thumb.

Grades are marks, not percentages

A grade is defined by a grade boundary — the minimum raw mark needed for it. Boards publish these as marks (e.g. "A*: 156 out of 200"), not percentages. You can turn that into a percentage (156/200 = 78%), but the percentage is a consequence of the boundary, not the definition of the grade.

Why the number moves every session

Boundaries are set after each exam, once examiners see how hard the paper turned out to be. If a paper was tougher than usual, boundaries drop so that students aren't punished for the setters' difficulty; if it was easier, they rise. This keeps the standard constant even though the percentage changes. So the same grade 7 might need 68% in one session and 74% in another — same standard, different percentage. Our boundaries guide goes deeper on this.

It also differs by subject and tier

• By subject: a 9 in a subject where top marks are common may need a higher percentage than a 9 in a subject where the paper is very demanding.
• By tier: because Extended/Higher papers are harder, a given grade often sits at a lower percentage than the same grade on Core/Foundation.
• By paper variant: different exam-zone variants of the same paper can have slightly different boundaries in the same session.

Rough guide (use with caution)

If you need ballpark figures for a 9–1 subject — and understanding they swing by ±5–10 points — recent sessions have tended to land near:

• Grade 9 — high 80s to 90%+
• Grade 7 — high 60s to mid 70s
• Grade 5 — around 50–60%
• Grade 4 (standard pass) — high 30s to ~50%

Treat these as orientation only. On tough Extended science papers, a 9 has needed well under 90%, and a pass well under 40%.

How to get the real number for your subject

Skip the guesswork — use the published data:

1. Open your subject's grade-to-percentage page — it lists the minimum percentage each grade required, from the latest real boundaries.
2. Or enter a mark into the grade calculator to see both the grade and the percentage for your exact session and paper variant.
3. Compare two or three sessions to see how much the figure actually moves — that spread is the real answer to "what percentage is a grade".

The takeaway

Don't revise to hit "70% = a 7". Revise to beat the mark that recent sessions' boundaries suggest, with a margin for a harder-than-usual paper. Aiming a comfortable buffer above the typical boundary is far safer than targeting a fixed percentage that may not apply the year you sit.

Independent study tool. Not affiliated with, endorsed by, or connected to Cambridge Assessment International Education or Pearson Edexcel. Grade boundary figures are sourced from official releases; always confirm with your exam board.