A-Level Maths grade boundaries: how they are set and what the marks really mean

The short answer is that no A-Level Maths grade has a fixed percentage. The boundary is decided after every paper in the country has been marked, and on Edexcel it has sat at roughly 84–86% of the 300 marks for an A* and 68–71% for an A over the last three summers. Those are good working figures, but they are a bracket and not a promise, and the way to use them is as a range to clear with room to spare rather than a number to hit exactly. Most of the arguments I hear about boundaries, from “you only need 70% for an A*” to “the boundary dropped, so it must have been a hard paper and I am fine”, come from treating a moving line as a fixed one.

How a boundary is actually set

Boundaries are not published in advance, because they cannot be. Exam boards set them once the marking is complete, using two kinds of evidence. The first is statistical: the board looks at how this year's entry performed at GCSE and predicts, from that, roughly what share of them should reach each grade, on the principle that a cohort of similar prior attainment should get broadly similar results to the one before. The second is human: senior examiners look at real scripts from around the marks the statistics point to and judge whether the work genuinely sits at the standard for that grade. The board then confirms the numbers, with Ofqual overseeing the system.

The principle underneath is that the standard is held steady and the mark is allowed to move. If the papers were harder than usual, the line comes down so that the same quality of work earns the same grade; if they were gentler, it goes up. That is why an A means the same thing from one summer to the next, and it is also why nobody, including me, can tell you in October exactly what a June paper will need. I explain a related point in the piece on whether the exam board matters: the harder-board, easier-board idea mostly dissolves once you see that the boundaries are built to cancel it out.

What the last three summers actually show

Here are Edexcel’s A-Level Maths (9MA0) boundaries out of 300, taken from Pearson’s published tables. In 2024 an A* took 251, an A 205, a B 167, a C 130 and an E 56. In 2025 it was 258, 214, 178, 142 and 71. In 2026 it was 254, 210, 173, 136 and 64.

Read down a column rather than across a row. The A* line moved within a seven-mark window over the three years, the A within nine, the C within twelve and the E within fifteen. So the lines do wobble, but by a handful of marks and not by dozens, and the wobble is larger lower down. As percentages, an A* has been 84–86%, an A 68–71%, a B 56–59%, a C 43–47% and an E 19–24%. In 2026 an A was exactly 210, which is 70%, and an A* was 254, about 85%.

Two of those numbers tend to surprise people. A B in 2026 needed 173 marks, which is 58%, and a score that feels like failure in the exam hall is often a perfectly respectable grade. And an E needed only around a fifth of the marks. I do not read that as passing being easy; I read it as a sign of how demanding the papers are, and it is the reason a 55% paper should not send anyone into a spiral.

Why “what percentage for an A*?” is the wrong question

There are two ways to get this wrong, and I see both every autumn. The first is the panic: a student scores 62% on a past paper, concludes they are a long way off an A, and starts revising in a way that feels urgent rather than useful. On the recent boundaries a 62% total would be a comfortable B, with an A six to nine points away. The second is the false comfort: a student scores 72% on a paper they found friendly, assumes an A is banked, and relaxes. One paper is one sample. The same student on a harder paper might score 60% and still be on course for the same grade, because the line would have fallen to match.

What the percentage hides is the size of the gap. The distance from an A to an A* in 2026 was 44 marks across three papers, around 15 a paper, and that is a much more concrete target than “90%”. I go through where those marks actually go in what separates an A from an A*, and it is almost never the content.

How to use the boundaries in your revision

Each A-Level paper is out of 100 marks, so a paper score is already a percentage of the 300 total, and the grade is decided on the combined total across all three papers. That means a strong paper can offset a weak one, which matters more than most students realise when one of the three is the applied paper they have been avoiding. Here is how I work with it.

First, mark honestly against the mark scheme. A generous total is worse than useless, because it moves you across a line you have not earned. I cover how to do that properly in the right and wrong ways to use past papers, and the papers themselves, for every board, are on the past papers hub.

Second, compare your total against your own board’s published boundaries for the last three years, not just the most recent one, and look at the bracket those three years form. A score that clears the top of the bracket for a grade is above the line in any recent year. A score inside the bracket is on the line: it could have gone either way, and you should treat it as the grade below. A score under the bracket is not there yet.

Third, average across papers. One result tells you very little; three or four timed papers in a row tell you where you actually are. I would rather a student told me they average 66% across four papers than that they once scored 81%.

Fourth, set the target with a cushion. Because the line can move by ten marks or so either way and you do not find out which way until August, I set my students’ target around ten marks above the top of the three-year bracket for the grade they want. That is not pessimism. It is the difference between needing the boundary to be kind and not caring what it does.

Near a boundary, one mark matters

Because the lines are single marks on a 300 scale, a student can finish a mark short of a grade, and in maths that is more likely to be an arithmetic slip somewhere than a gap in understanding. If it happens on the day, what to do if maths did not go to plan sets out the options and the honest odds of each, and the first step is always to ask for the mark breakdown and look at the distance to the line before deciding anything.

The same logic applies elsewhere, with different numbers

Further Maths boundaries are set on a different, self-selecting cohort, which gives them their own quirks, and I explain those in the guide to whether Further Maths is worth it. GCSE works on the same principle but with a twist, because the tier you sit changes what a mark is worth, which is the heart of the foundation or higher decision. And a school’s own mock boundaries are not the exam board’s: they are often set to motivate rather than to mirror the summer, which is one reason what December mock results really predict is a different question from what a mock grade says.