OCR A-level Chemistry grade boundaries 2025: Chemistry A and Salters

OCR A-level Chemistry grade boundaries 2025

These are the figures in OCR's June 2025 A Level boundaries document (version 1.0, 14 August 2025). OCR has two Chemistry A-levels, so there are two columns. The boundary is the lowest total mark for the grade.

Chemistry A is the course in our OCR A-level Chemistry guide, and the OCR A-level Chemistry data sheet lists what you are given in the exam. The board-wide A-level boundaries for 2025 cover the other subjects.

The highest A* share of any OCR science

Chemistry A needs 243 out of 270 for an A*, which is 90% of the marks. Physics A's A* was 76% that year, and Biology A's was 69%. A high A* line goes with a low E line: Chemistry A's E was 61, or 23%. The range between the two is wider than in any other OCR A-level science, which is why a Chemistry A candidate in the middle of the grades can be a long way from the top.

Chemistry A paper by paper, 2025

In Chemistry A, Paper 1 (Periodic table, elements and physical chemistry) and Paper 2 (Synthesis and analytical techniques) were almost identical at the top, 92 and 91 for an A*. The Unified paper needed 60 out of 70, 86%. Chemistry B has Fundamentals (110 marks), Scientific literacy (100) and Practical skills (60). Its Scientific literacy paper needed 78 out of 100 for an A*. OCR's paper boundaries are for information, and the grade comes from the total.

How 2025 compares with 2024

Chemistry A edged up through the grades: the A from 212 to 213, the C from 134 to 137 and the E from 58 to 61. The 2024 numbers are in OCR's document of 15 August 2024. Chemistry B fell at every grade: the A went from 186 to 176, a drop of 10 marks, and the E from 69 to 59. Ofqual says boundaries vary from year to year to reflect the difficulty of each paper. A 10 mark fall at A is a large move, and it means the 2025 Salters papers were harder to score on.

AS Chemistry 2025

Both AS courses are out of 140 and have no A*. Chemistry A (H032) fell from an A of 117 in 2024 to 113. Chemistry B (H033) hardly moved, at an A of 94 against 93 the year before.

Marks to grade: two Chemistry examples

• Chemistry A. A candidate scores 80 on Paper 1, 78 on Paper 2 and 50 on Paper 3, so 208 out of 270. The 2025 boundaries are 213 for an A and 175 for a B. 208 is above 175 and below 213, so the grade is a B, 5 marks short of an A. In 2024 the A line was 212, so the same total would have been a B then too.
• Chemistry B. 78 on Fundamentals (out of 110), 66 on Scientific literacy (out of 100) and 44 on Practical skills (out of 60) make 188. The A line was 176 and the A* line 216, so the grade is an A, 28 marks short of an A*.

OCR's How do we calculate your A Level grade? explains the method: total the component marks and compare the total with the boundaries.

Chemistry advice from the 2025 numbers

• Aim for accuracy on the calculations. An A* at 90% leaves room for only about 27 lost marks.
• Use the Unified paper. Paper 3 draws on all six modules and is 26 per cent of the grade.
• Check your suite. The A* gap between Chemistry A and B in 2025 was 27 marks.
• Remember the practical endorsement. It is a separate pass and does not add marks to the 270.

Practise with today's A-level Chemistry paper

Chemistry Advanced 1 and Chemistry Advanced 2 each give a short timed paper of 8 questions. They are not OCR papers, so use the percentage as a guide. In 2025 the Chemistry A grade B line was 65% and the A line 79%.

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