IB Biology SL Grade Boundaries: 72-81% for a 7

Overall boundaries, every session on record

Minimum scaled mark, out of 100, for each grade in IB Biology SL. One row per session and timezone; May 2021 and 2022 and November 2021 and 2022 show the examination route.
Session	7	6	5	4	3	2	Gap 6 to 7
November 2025 TZ3	77	64	52	39	24	14	13
November 2025 TZ1	78	66	52	40	25	14	12
May 2025 TZ3	72	59	46	33	21	11	13
May 2025 TZ2	72	60	48	36	24	13	12
May 2025 TZ1	77	64	52	39	26	13	13
November 2024 TZ2	81	68	55	43	29	16	13
November 2024 TZ1	76	64	52	40	26	14	12
May 2024 TZ2	75	63	50	38	25	15	12
May 2024 TZ1	76	64	52	40	27	15	12
November 2023 TZ2	79	66	54	41	27	15	13
November 2023 TZ1	78	65	52	39	27	15	13
May 2023 TZ2	74	62	50	38	26	15	12
May 2023 TZ1	76	64	51	39	26	15	12
November 2022 (exam route)	78	65	51	39	26	15	13
May 2022 TZ2 (exam route)	76	61	48	33	22	13	15
May 2022 TZ1 (exam route)	79	64	49	34	24	14	15
November 2021 (exam route)	77	63	47	35	23	14	14
May 2021 TZ2 (exam route)	75	59	44	31	22	12	16
May 2021 TZ1 (exam route)	74	60	44	32	21	12	14
November 2020	75	63	51	39	26	15	12
November 2019	79	66	55	42	27	15	13
May 2019 TZ2	72	59	48	35	24	14	13
May 2019 TZ1	78	66	54	43	31	17	12
November 2018	75	62	51	39	26	15	13
May 2018 TZ2	75	63	49	37	25	14	12
May 2018 TZ1	76	64	51	39	27	15	12
May 2017 TZ2	74	61	48	36	24	14	13
May 2017 TZ1	74	62	48	36	26	15	12

What do I need

IB Biology SL: the mark you need, paper by paper

Session

Grade

In May 2025 TZ3 a 7 overall started at 72 out of 100 scaled marks. On each component:

Component	Out of	Minimum for a 7	As %
Internal assessment (practical work)	24	20	83%
Paper 1A (multiple choice)	30	22	73%
Paper 1B	25	18	72%
Paper 2	50	35	70%

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

Sessions in which schools that could not sit written examinations were graded on coursework and predicted evidence. The IB issued a separate boundaries document for that route.
Session	7	6	5	4	3	2	Gap 6 to 7
November 2022 (non-exam route)	78	65	51	39	26	15	13
May 2022 TZ2 (non-exam route)	75	63	51	36	22	13	12
May 2022 TZ1 (non-exam route)	79	67	49	34	24	14	12
November 2021 (non-exam route)	83	67	57	46	34	18	16
May 2021 TZ2 (non-exam route)	72	59	48	35	24	14	13
May 2021 TZ1 (non-exam route)	78	66	54	43	31	17	12

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 77% in TZ3 and at 78% 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 Biology SL has averaged 75% in May and 77.5% 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 Biology SL the 6 sits on average 12.9 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 81% or more on full mocks under exam conditions has a 7 in every session on record. A student at 72% 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 grade boundaries overview, as CSV and JSON.

Independent work, not endorsed by the International Baccalaureate. Last checked 4 November 2026. Corrections: pietro@pietromeloni.com.

Frequently asked questions

What percentage do you need for a 7 in IB Biology SL?

77% of the scaled marks in November 2025 TZ3. Over 16 sessions since May 2017 TZ1 the 7 has started between 72% and 81%, 76% on average. There is no fixed figure: the IB sets the boundaries after each session, once the papers have been marked.

How many marks separate a 6 from a 7 in Biology SL?

Between 12 and 16 on the 100-mark scale, 12.9 on average. In November 2025 TZ3 it was 13 marks. That is the size of one question answered fully instead of half-answered, which is why exam technique moves this grade more than new content.

Are Biology SL grade boundaries going up or down?

The May 7 moved from 75% in May 2024 TZ2 to 72% in May 2025 TZ3. A move of a few points between years is normal and reflects how hard that paper was, not a change in the standard.

Is November easier than May in Biology SL?

Not in the boundaries: the 7 has averaged 75% in May sessions and 77.5% in November sessions on record. The IB sets both to the same standard, so a difference of a point or two reflects the papers of those sessions, not a softer session.

Where do these numbers come from?

Every row on this page was read from the grade boundaries document the IB issues to Diploma Programme coordinators after each session, for all 16 sessions shown. The document lists, for every subject and level, the minimum raw mark for each grade on each component and the minimum scaled mark out of 100 for the overall grade.

IB Biology SL grade boundaries: what you need for a 7