If you are reading this, the chances are you have just looked at a mock paper, seen a percentage, and tried to translate it into a grade. That translation is what grade boundaries do — and they are one of the least-explained parts of the GCSE system. This guide is the founder note I would send a parent who messaged me on a Sunday evening asking, calmly, whether 58% on a Higher maths mock was a 5 or a 6. The honest answer is "it depends on the year" — and what to do about that is, mercifully, knowable.
What grade boundaries are
A grade boundary is the minimum mark a candidate needs, on a given paper, in a given year, to be awarded a given grade. They are set per exam board, per subject, per tier (Foundation or Higher), and per series (summer 2025, November 2025, summer 2026 and so on). A "55" in AQA Higher Maths in 2024 is not the same achievement as a "55" in AQA Higher Maths in 2023, because the papers are different and the boundaries move with them.
The numerical 9-1 system, brought in for English and Maths in 2017 and rolled out across the rest of the GCSE suite by 2019, does not change this. A 9 is still a 9 because the boundary was set so that roughly the top fraction of candidates earn one — not because there is a fixed mark like "85% gets you a 9". There never has been.
On Combined Science, the boundaries describe a combined-mark threshold across the six papers (Biology 1, Biology 2, Chemistry 1, Chemistry 2, Physics 1, Physics 2) and award a double grade like 7-7 or 6-5. On the single sciences, each subject has its own boundaries, set independently. Mock papers from your school may use last year's official boundaries, the school's own internal ones, or a hybrid — it is worth asking which.
How they shift year-on-year
Boundaries are set after the papers are sat and marked, by a panel that includes senior examiners and the regulator (Ofqual in England). The panel adjusts for whether a particular paper turned out harder or easier than intended. If the cohort as a whole found a paper harder, the boundary for a 7 will fall; if it was easier, the boundary will rise. The intent is comparable outcomes: a child who would have earned a 7 in 2023 should earn a 7 in 2024 even if their raw mark is different.
That principle has been stress-tested in the last few years. Grading was generous in 2020 and 2021 because exams were cancelled or disrupted; it returned to a 2019-style baseline in 2023; 2024 and 2025 have continued in that calmer pattern. The headline you sometimes hear — "boundaries jumped this year" — usually means the 2024 or 2025 boundary moved closer to the long-run average after a pandemic-era softening. It does not mean exams suddenly got easier or that your child's prep was wasted.
Movement is also paper-by-paper. A grade 7 in AQA Higher Maths and a grade 7 in OCR Higher Maths in the same summer can rest on different raw marks because the papers are different and the cohorts are different. If your child sits one board and their cousin sits another, do not compare percentages — compare grades.
What the 2025 boundaries looked like
When the awarding-body data lands, this section will list the 2025 boundaries for the papers parents most often ask about — AQA Higher and Foundation Maths, AQA English Language, AQA Combined Science Trilogy, and the Maths equivalents on Edexcel and OCR — with each row linked to the original boundaries document on the awarding body's site. The aim is a table you can show your child without us inventing a single number.
In the meantime, the awarding bodies publish the official boundaries on their own sites the morning of results day each August, and they remain freely available afterwards. Search for "AQA grade boundaries summer 2025" (or OCR or Pearson Edexcel) and you will find the source PDFs.
What this means for your child
First and most importantly: a percentage on a mock paper is not, on its own, a grade. To convert a mock mark into a grade you need three things: the paper, the tier, and the boundaries the marker used. Ask the school which boundary set they applied. If it is "last year's official boundaries", that is a reasonable proxy. If it is "internal", treat the grade as directional rather than predictive.
Second: tier matters more than people think. On most subjects (Maths, the sciences, French, German) there is a Foundation tier capped at grade 5 and a Higher tier running 4-9. A child sitting Foundation cannot achieve a 6, no matter how high they score. A child sitting Higher who underperforms can fail to record a grade if they fall below the safety-net mark. The tier decision — usually made in the spring of Year 11 — therefore moves the ceiling and the floor at once. If you are not certain which tier your child is on, ask the subject teacher in writing this week. We have written more about how we approach tier and prep on our how it works page.
Third: raw-mark distance matters. The practical question is not "what grade did they get" but "how many marks short of the next grade were they". Five marks below a 7 boundary on a 80-mark paper is a different conversation from twenty marks below. The first is a small, identifiable gap; the second is a structural one. Both are workable, but the plan is different.
Fourth: compare like with like. A grade in a November mock taken in classroom conditions, with a marker who knows your child, is not the same data point as a grade in a spring mock sat under exam conditions in the school hall. Borderline is meaningful in the second case in a way that it is not in the first.
What to do if your mock is borderline
Borderline means the next grade is reachable in the time you have left, not that it will arrive on its own. Three things actually move the needle.
1. Diagnose the gap, do not guess at it
Re-read the paper with your child, not for marks scored but for marks lost. Sort the lost marks into three piles: topics they have not been taught, topics they have been taught but cannot apply under time pressure, and silly errors (misread the question, dropped a unit, wrong sign). The three piles need different responses, and confusing them is the most common reason a borderline mock turns into a borderline final.
If you would like an outside pair of eyes on this, our £97 Legacy Diagnostic is exactly this: a specialist tutor sits with the mock, sorts the lost marks honestly, and writes you a one-page plan. It is not a sales call dressed as a service — it is the same conversation we'd have with a parent on a Sunday evening, just scheduled and on paper.
2. Practise the paper, not just the topic
Most revision before a mock is topic-based: a chapter on quadratics, a chapter on cells. Most marks lost in a borderline result are not topic-not-known marks; they are question-not-answered-the-way-the-mark-scheme-wants marks. The fix is to do real past papers under real timing, then mark them against the official mark scheme — not the textbook answer key. Two papers a week, marked properly, beats four hours of scrolling revision videos. This is true on Maths, and it is especially true on GCSE English Language and the longer-write science questions.
3. Get the high-leverage hours back
On GCSE Maths in particular, the difference between a 5 and a 6, or a 7 and an 8, often sits in three or four high-frequency topic areas — algebraic manipulation, ratio, probability, and the longer problem-solving questions worth 4–6 marks each. Twelve focused hours on those, with a tutor who has marked the same board's papers, will move a borderline result more reliably than forty unstructured hours of "revision" alone. The same is true on the long-answer questions in Combined Science and on the Paper 2 reading section in English Language.
Closing thought, parent-to-parent
Boundaries feel arbitrary until you understand the system, and then they feel — accurately — like a moving target you can nevertheless aim at. The parents I speak to who keep their head through the spring are the ones who have stopped asking "what grade is this percentage" and started asking "what is the smallest, most identifiable thing standing between my child and the next grade up". The honest answer is rarely "more revision". It is usually "this specific gap, fixed by this specific person, in these specific weeks".
If you'd like help building that plan, the fastest route is the £97 Legacy Diagnostic — a specialist tutor, a real mock, a real plan. If you'd rather start with subject context, our GCSE Maths tutoring page explains how we work on the subject most-discussed for boundary movement. And if you simply want to keep reading, the rest of our parent guides live on the resources hub.