Overall boundaries, every session on record
| Session | 7 | 6 | 5 | 4 | 3 | 2 | Gap 6 to 7 |
|---|---|---|---|---|---|---|---|
| November 2025 TZ3 | 75 | 65 | 54 | 43 | 28 | 15 | 10 |
| November 2025 TZ1 | 76 | 66 | 55 | 44 | 28 | 15 | 10 |
| May 2025 TZ3 | 70 | 58 | 47 | 36 | 24 | 14 | 12 |
| May 2025 TZ2 | 72 | 61 | 49 | 38 | 28 | 16 | 11 |
| May 2025 TZ1 | 71 | 60 | 49 | 38 | 28 | 16 | 11 |
| November 2024 | 75 | 65 | 55 | 44 | 29 | 16 | 10 |
| May 2024 TZ2 | 72 | 60 | 48 | 37 | 28 | 16 | 12 |
| May 2024 TZ1 | 73 | 61 | 50 | 38 | 26 | 15 | 12 |
| November 2023 TZ2 | 73 | 63 | 53 | 43 | 27 | 15 | 10 |
| November 2023 TZ1 | 73 | 63 | 53 | 43 | 27 | 15 | 10 |
| May 2023 TZ2 | 72 | 60 | 49 | 38 | 28 | 15 | 12 |
| May 2023 TZ1 | 74 | 62 | 50 | 39 | 26 | 15 | 12 |
| November 2022 (exam route) | 71 | 60 | 50 | 39 | 24 | 11 | 11 |
| May 2022 TZ2 (exam route) | 69 | 56 | 46 | 33 | 22 | 10 | 13 |
| May 2022 TZ1 (exam route) | 73 | 61 | 48 | 36 | 23 | 11 | 12 |
| November 2021 (exam route) | 70 | 56 | 44 | 31 | 19 | 9 | 14 |
| May 2021 TZ2 (exam route) | 76 | 61 | 46 | 24 | 10 | 5 | 15 |
| May 2021 TZ1 (exam route) | 72 | 55 | 42 | 27 | 14 | 7 | 17 |
| November 2020 | 75 | 64 | 51 | 40 | 27 | 15 | 11 |
| November 2019 | 76 | 65 | 55 | 44 | 29 | 15 | 11 |
| May 2019 TZ2 | 79 | 68 | 58 | 46 | 33 | 17 | 11 |
| May 2019 TZ1 | 78 | 65 | 55 | 43 | 29 | 16 | 13 |
| November 2018 | 74 | 62 | 53 | 41 | 27 | 15 | 12 |
| May 2018 TZ2 | 73 | 62 | 52 | 40 | 28 | 15 | 11 |
| May 2018 TZ1 | 76 | 63 | 53 | 41 | 29 | 16 | 13 |
| May 2017 TZ2 | 72 | 61 | 51 | 40 | 28 | 15 | 11 |
| May 2017 TZ1 | 71 | 60 | 50 | 39 | 28 | 15 | 11 |
What do I need
IB Chemistry SL: the mark you need, paper by paper
In May 2025 TZ3 a 7 overall started at 70 out of 100 scaled marks. On each component:
| Component | Out of | Minimum for a 7 | As % | Your raw mark | Your grade |
|---|---|---|---|---|---|
| Internal assessment (practical work) | 24 | 20 | 83% | ||
| Paper 1A (multiple choice) | 29 | 22 | 76% | ||
| Paper 1B | 25 | 16 | 64% | ||
| Paper 2 | 50 | 34 | 68% |
Component grades come straight from the IB document for that session. The overall grade is on a 100-mark scale built from the components with the weightings in the subject guide, so it is not computed here: a strong component carries a weaker one, and the table shows how much room each one leaves.
Non-examination route, 2021 and 2022
| Session | 7 | 6 | 5 | 4 | 3 | 2 | Gap 6 to 7 |
|---|---|---|---|---|---|---|---|
| November 2022 (non-exam route) | 79 | 66 | 52 | 39 | 24 | 11 | 13 |
| May 2022 TZ2 (non-exam route) | 85 | 72 | 62 | 49 | 38 | 26 | 13 |
| May 2022 TZ1 (non-exam route) | 83 | 71 | 58 | 46 | 33 | 21 | 12 |
| November 2021 (non-exam route) | 78 | 67 | 57 | 46 | 31 | 17 | 11 |
| May 2021 TZ2 (non-exam route) | 79 | 68 | 58 | 46 | 33 | 17 | 11 |
| May 2021 TZ1 (non-exam route) | 78 | 65 | 55 | 43 | 29 | 16 | 13 |
Timezones: the same session, different papers
In May the IB sets different papers for different parts of the world, and each gets its own boundaries. In November 2025 the 7 started at 75% in TZ3 and at 76% in TZ1.
A gap between timezones is not an advantage for one of them: the boundary follows the paper. The useful reading is the range across all timezones and sessions, which is what the first table shows.
May against November
On record the 7 in Chemistry SL has averaged 73.1% in May and 73.8% in November. The two sessions are set to the same standard; the difference is the papers, not the season.
The gap between a 6 and a 7
In Chemistry SL the 6 sits on average 11.8 marks below the 7 on the 100-mark scale. That is roughly one question answered fully instead of half-answered, or the marks lost to misread instructions across a whole paper.
Use the range, not the last session. A student scoring 79% or more on full mocks under exam conditions has a 7 in every session on record. A student at 69% has a 7 only on the hardest paper, and should plan for the 6 to 7 gap rather than assume it.
Sources
All 16 sessions were read from the grade boundaries document the IB issues to Diploma Programme coordinators after each session (one document per session; 2021 and 2022 have an examination-route and a non-examination-route document). The full dataset for every IB subject is on the
Independent work, not endorsed by the International Baccalaureate. Last checked . Corrections: pietro@pietromeloni.com.
Frequently asked questions
What percentage do you need for a 7 in IB Chemistry SL?
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How many marks separate a 6 from a 7 in Chemistry SL?
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Are Chemistry SL grade boundaries going up or down?
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Is November easier than May in Chemistry SL?
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Where do these numbers come from?
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