Every exam series, parents ask the same question when results arrive: “How many marks was an A this time?” Grade boundaries are the answer — and understanding how they work removes a lot of unnecessary worry.
What a Grade Boundary Is
A grade boundary is the minimum mark needed for a particular grade on a particular paper, in a particular series. For example, an A might require 80% in one series. Boundaries are published by Cambridge after each exam, and they apply across the combined papers a student sits.
Why They Move Every Series
Boundaries are not fixed. Cambridge adjusts them each series to account for how difficult that specific paper turned out to be. If a paper was harder than usual, the boundaries are lowered so that a student of a given ability earns the same grade they would have on an easier paper. This is a fairness mechanism, not a curve that pits students against each other.
What This Means in Practice
Two consequences matter for parents. First, a slightly lower raw mark doesn’t necessarily mean a lower grade — it depends on that series’ boundaries. Second, you can’t know the exact mark needed in advance, so the safe target is always comfortably above the typical boundary, not right on it.
Using Past Boundaries Wisely
Looking at several past series gives a realistic range for each grade. Aiming for the top of that range builds in a safety margin against a tough paper.
Want to know where your child stands against realistic boundaries? Book a trial class for a mark-scheme-based assessment.
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