Group 4: Sciences

IB Biology SL grade boundaries

Every published cutoff for IB Biology SL, by exam session and timezone. The historical graph below shows how each grade has shifted over time.

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At a glance

Sessions12

Latest sessionNovember 2025

Level

Grade boundary table

Every published cutoff. Most recent session first; timezone variants are listed within each session.

12 sessions22 rows

Session	TZ	Grade 1	Grade 2	Grade 3	Grade 4	Grade 5	Grade 6	Grade 7
November 2025latest	TZ1	0%	14%	25%	40%	52%	66%	78%
November 2025	TZ3	0%	14%	24%	39%	52%	64%	77%
May 2025	TZ1	0%	13%	26%	39%	52%	64%	77%
May 2025	TZ2	0%	13%	24%	36%	48%	60%	72%
May 2025	TZ3	0%	11%	21%	33%	46%	59%	72%
November 2024	TZ1	0%	14%	26%	40%	52%	64%	76%
November 2024	TZ2	0%	16%	29%	43%	55%	68%	81%
May 2024	TZ1	0%	15%	27%	40%	52%	64%	76%
May 2024	TZ2	0%	15%	25%	38%	50%	63%	75%
November 2023	TZ1	0%	15%	27%	39%	52%	65%	78%
November 2023	TZ2	0%	15%	27%	41%	54%	66%	79%
May 2023	TZ1	0%	15%	26%	39%	51%	64%	76%
May 2023	TZ2	0%	15%	26%	38%	50%	62%	74%
November 2022	TZ1	0%	15%	26%	39%	51%	65%	78%
May 2022	TZ1	0%	14%	24%	34%	49%	64%	79%
May 2022	TZ2	0%	13%	22%	33%	48%	61%	76%
May 2021	TZ1	0%	12%	21%	32%	44%	60%	74%
May 2021	TZ2	0%	12%	22%	31%	44%	59%	75%
November 2020	TZ1	0%	15%	26%	39%	51%	63%	75%
November 2019	TZ1	0%	15%	27%	42%	55%	66%	79%
May 2019	TZ1	0%	17%	31%	43%	54%	66%	78%
May 2019	TZ2	0%	14%	24%	35%	48%	59%	72%

Historical grade boundaries

Every published boundary across 12 sessions. Multiple dots per session are timezone variants.

12 sessions22 data points

Best place to gain marks

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Common questions

Where can I find historical IB Biology SL grade boundaries?

This page lists every published IB Biology SL boundary across recent exam sessions, with timezone variants where they apply, plus a graph that traces each grade cutoff over time.

What if a boundary is missing for IB Biology SL?

If the IBO has not released boundaries for a given session, the table omits that row. The graph reuses any earlier session that does have a published boundary so trends remain visible.

Are these IB Biology SL boundaries official?

The numbers are taken from official IB grade boundary documents. They are reproduced here for reference and do not modify the published cutoffs.

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