Edexcel IAL Grade Boundaries June 2026: Every Biology and Chemistry Unit, What should you do next?
Raw and UMS marks for WBI11–WBI16 and WCH11–WCH16, the June 2025 comparison, and a UMS calculator for your exact paper.
TL;DR: Pearson published the June 2026 IAL grade boundaries on results day, 13 August 2026. Chemistry Unit 4 (WCH14) saw the biggest single move — the a* boundary fell 7 raw marks to 74/90 — while Biology Unit 5 (WBI15) rose 5 marks to 72/90. The variant papers split hard this session: Chemistry Unit 2 and Unit 2A sit 16 raw marks apart for the same grade. Every Biology and Chemistry unit is tabled below with the June 2025 comparison, and you can convert your own raw mark to UMS with the calculator further down the page.
On this page:
- What are the IAL grade boundaries for June 2026?
- IAL Biology grade boundaries June 2026 (WBI11–WBI16)
- IAL Chemistry grade boundaries June 2026 (WCH11–WCH16)
- What the June 2026 changes tell you
- Why is your variant (A) paper boundary different?
- Convert your raw mark to UMS
- Should you retake a unit? What I tell my students
- FAQ
What are the IAL grade boundaries for June 2026?
The June 2026 IAL grade boundaries are the minimum raw marks needed for each grade in every International AS and A2 unit, published by Pearson on results day, 13 August 2026. You can download the official file from the Pearson grade boundaries page, filtered for International Advanced Level.
Two things stand out this session before you even find your row. First, the two subjects moved in opposite directions at the top: the hardest Chemistry boundary to reach is WCH15's variant paper at 82 out of 90 for an a* — that's 91% — while Chemistry Unit 4 became noticeably kinder. Second, the variant (A) papers carried unusually different boundaries from the main papers. Chemistry Unit 2 needed 65/80 for an a; its 2A variant needed just 49. Sixteen raw marks, same unit, same grade. If you sat a variant paper, check the right row before you draw any conclusion about your performance.
This morning I had over 45 messages from students checking their results with me, and the mood was very different from most results days: most of them performed well above what they expected. That has been the pattern with my students for six years running now, and I'll come back to why further down, because it matters for anyone weighing up a retake.
IAL Biology grade boundaries June 2026 (WBI11–WBI16)
Biology boundaries rose almost across the board in June 2026, with the a boundary for WBI11 up 4 marks and the a* for WBI15 up 5. Here is every Biology unit — raw marks, with last June's top boundary alongside for comparison.
| Unit | Max | a* | a | b | c | d | e | Top grade, June 2025 | Change |
|---|---|---|---|---|---|---|---|---|---|
| WBI11 – Molecules, Diet, Transport and Health | 80 | — | 58 | 51 | 45 | 39 | 33 | 54 | +4 |
| WBI11 (1A variant) | 80 | — | 58 | 51 | 45 | 39 | 33 | — | — |
| WBI12 – Cells, Development, Biodiversity and Conservation | 80 | — | 58 | 51 | 44 | 37 | 31 | 57 | +1 |
| WBI12 (2A variant) | 80 | — | 57 | 50 | 43 | 37 | 31 | — | — |
| WBI13 – Practical Skills in Biology I | 50 | — | 36 | 31 | 26 | 21 | 17 | 38 | −2 |
| WBI13 (3A variant) | 50 | — | 38 | 33 | 28 | 24 | 20 | — | — |
| WBI14 – Energy, Environment, Microbiology and Immunity | 90 | 62 | 56 | 50 | 44 | 38 | 32 | 61 | +1 |
| WBI14 (4A variant) | 90 | 63 | 57 | 51 | 45 | 39 | 33 | — | — |
| WBI15 – Respiration, Internal Environment, Coordination and Gene Technology | 90 | 72 | 64 | 56 | 48 | 40 | 33 | 67 | +5 |
| WBI15 (5A variant) | 90 | 72 | 64 | 56 | 48 | 41 | 34 | — | — |
| WBI16 – Practical Skills in Biology II | 50 | 45 | 41 | 36 | 31 | 26 | 22 | 43 | +2 |
| WBI16 (6A variant) | 50 | 45 | 40 | 35 | 30 | 25 | 21 | — | — |
The one Biology unit that got easier to grade well on paper is WBI13, the AS practical unit, down 2 marks for an a. Everything else asked a little more of you than last June — and WBI15 asked quite a lot more. If you're an AS student reading this to plan next year, note that the AS cash-in (XBI11) still needs 240 out of 300 UMS for an A; those totals never move.
IAL Chemistry grade boundaries June 2026 (WCH11–WCH16)
Chemistry split both ways in June 2026: Unit 1 and Unit 4 boundaries fell, Units 2, 3 and 5 rose. Here is every Chemistry unit, again with last June's top boundary for comparison.
| Unit | Max | a* | a | b | c | d | e | Top grade, June 2025 | Change |
|---|---|---|---|---|---|---|---|---|---|
| WCH11 – Structure, Bonding and Introduction to Organic Chemistry | 80 | — | 59 | 52 | 45 | 38 | 31 | 64 | −5 |
| WCH11 (1A variant) | 80 | — | 60 | 52 | 44 | 37 | 30 | — | — |
| WCH12 – Energetics, Group Chemistry, Halogenoalkanes and Alcohol | 80 | — | 65 | 56 | 48 | 40 | 32 | 60 | +5 |
| WCH12 (2A variant) | 80 | — | 49 | 42 | 36 | 30 | 24 | — | — |
| WCH13 – Practical Skills in Chemistry I | 50 | — | 40 | 34 | 28 | 22 | 16 | 36 | +4 |
| WCH13 (3A variant) | 50 | — | 31 | 27 | 23 | 19 | 16 | — | — |
| WCH14 – Rates, Equilibria and Further Organic Chemistry | 90 | 74 | 66 | 58 | 50 | 42 | 34 | 81 | −7 |
| WCH14 (4A variant) | 90 | 69 | 61 | 53 | 45 | 38 | 31 | — | — |
| WCH15 – Transition Metals and Organic Nitrogen Chemistry | 90 | 77 | 68 | 59 | 51 | 43 | 35 | 73 | +4 |
| WCH15 (5A variant) | 90 | 82 | 74 | 66 | 58 | 51 | 44 | 73 | +9 |
| WCH16 – Practical Skills in Chemistry II | 50 | 41 | 37 | 33 | 30 | 27 | 24 | 39 | +2 |
| WCH16 (6A variant) | 50 | 36 | 32 | 28 | 25 | 22 | 19 | — | — |
Read the WCH15 variant row twice if you sat it: 82 out of 90 for an a* is the highest boundary in either subject this session, and it means a near-flawless paper. The A level cash-in (YCH11) is unchanged as always: 480 out of 600 UMS for an A, 240 out of 300 for an A at AS. For the full official tables across all subjects, the June 2025 boundaries document sits alongside the new file on Pearson's site, which is exactly how the comparisons above were built.
What the June 2026 changes tell you
A falling boundary means a harder paper, and a rising one means a more accessible paper — Pearson moves raw boundaries each session precisely so that a grade represents the same standard year after year. That's the lens for reading this June's shifts.
Chemistry Unit 4 (WCH14), down 7 marks for the a*. Having worked through this session’s Unit 4 paper with my classes, I can tell you it was slightly harder than last year’s, and the boundary drop is the system doing its job — reflecting that difficulty back so nobody is punished for sitting a tougher paper. If your raw mark on Unit 4 looks lower than your mocks predicted, look at the boundary before you look for blame.
Biology Unit 5 (WBI15), up 5 marks for the a*. The opposite story. This June's paper was more straightforward, and the scientific article questions in particular were quite predictable — predictable enough that teachers who prepared their classes on the pre-release article could anticipate the question angles well. Students walked into that exam with a clear idea of what the article questions would look like, marks rose across the cohort, and the boundary rose with them. It's a useful lesson for next year's Unit 5 candidates: the article rewards structured preparation more than any other part of the IAL Biology course.
The practical units moved in opposite directions by subject. Chemistry's AS practical (WCH13) rose 4 marks while Biology's (WBI13) fell 2 — a reminder that practical papers are the most volatile boundaries in the qualification, something I flagged when the January 2026 IAL grade boundaries came out, and June has repeated the pattern.
Why is your variant (A) paper boundary different?
Variant (A) papers are different exam papers sat in different regions or timezones, so Pearson sets their boundaries separately — each paper's boundary reflects that paper's difficulty, not the unit's. That is why WCH12 and its 2A variant can sit 16 raw marks apart for the same grade in the same session.
This catches students out every results day. Two friends compare marks on "Unit 2", one scored 55 and got an a, the other scored 60 and got a b — and it feels unfair until you realise they sat different papers. The 2A paper this June was clearly the tougher one, so its a boundary sits at 49 while the main paper's sits at 65. Both grades represent the same standard of chemistry.
So before you compare marks with anyone, or measure yourself against a boundary table, confirm which paper you sat. Your school's exams officer can tell you, and your statement of results works in UMS precisely so that this comparison problem disappears — which brings us to the calculator.
Convert your raw mark to UMS
UMS (Uniform Mark Scale) is the fixed scale your raw mark is converted to, and UMS boundaries never change: 96 out of 120 is an a on every full unit, in every session. All the year-to-year movement you see in the tables above lives in the raw marks; the UMS scale is the stable currency your grades are added up in, as Pearson explains in the notes accompanying every grade boundaries release.
Use the calculator above by picking your subject, your unit (including the A variant if that's the paper you sat), and typing your raw mark. It converts using Pearson's published June 2026 boundary points, with marks between boundaries scaled proportionally, the standard method. A quick worked example: 58 out of 80 on WBI11 is exactly the a boundary this session, so it converts to exactly 96 UMS out of 120.
One caution: the calculator gives you the correct June 2026 conversion, but your official UMS is the one printed on your statement of results. If the two ever disagree, the statement wins — and a disagreement is worth a conversation with your exams officer.
Should you retake a unit? What I tell my students
A retake decision rests on three things: your actual unit marks, your university's entry requirements, and whether a higher grade is the thing standing between you and your offer. It is not automatic, and it is not a verdict on you.
Because IAL is modular, a small drop in one unit is rarely fatal. If one unit slipped to a high b, an overall A — even an A* — is still very much on the table, provided you perform strongly in your remaining units. I've watched students do exactly this every year. The UMS system means every mark in every unit counts towards the same total, so one below-target unit can be outweighed rather than retaken.
When a retake is the right call, here is what works. The students of mine who improve in October or January are the ones who change their mindset and their study system — not the ones who simply sit the same preparation twice. Check your transcript, find the units and question types where the marks went missing, and repair those specific flaws. That diagnostic-first approach is the entire philosophy behind my AS Chemistry course and AS Biology course, and it's why the improvement I mentioned at the top of this post — students beating their own expectations — has held steady for six years. For A2 students resitting Unit 4 or 5, the A2 Biology course follows the same transcript-first method, and my IAL revision eBooks are updated against the latest mark schemes so you're repairing against what examiners credit now, not what they credited three years ago.
If you'd like a second pair of eyes on your transcript before you decide anything, message me on WhatsApp at +965 5137 5709 or email admin@chem-bio.info — that's precisely the conversation those 45 results-day messages were about.
FAQ
Do UMS grade boundaries change each session? No — UMS boundaries are fixed: 96/120 for an a, 84 for a b, 72 for a c on every full unit, every session. Only the raw mark boundaries move, to reflect each paper's difficulty.
Are the June 2026 IAL boundaries higher than June 2025? Mostly yes in Biology, mixed in Chemistry: Biology rose in five of six units, while Chemistry Units 1 and 4 fell and Units 2, 3 and 5 rose. The largest moves were WCH14 down 7 raw marks and WBI15 up 5.
What mark do I need for an a* in an A2 unit? Pearson publishes a theoretical a* boundary for every A2 unit, and on the UMS scale it always sits at 90%: 108/120 on full units and 54/60 on practical units. In raw marks for June 2026, that ranged from 62/90 on WBI14 up to 82/90 on the WCH15 variant.
Can I retake an IAL unit, and when? Yes — IAL units can be resat in the October and January series, and your better result counts towards your qualification. Base the decision on your transcript and your university requirements, not on disappointment alone.
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