What was the mean grade in IB Biology in May 2026?

The mean was 4.5 at Higher Level and 4.3 at Standard Level, on a scale of 1 to 7. These figures come from the IB's provisional statistical bulletin for May 2026.

Did IB Biology grades change compared with May 2025?

The mean grades did not change: 4.5 at HL and 4.3 at SL in both May 2025 and May 2026. Because means are given to one decimal place, very small shifts would not show.

Is HL Biology scored higher than SL?

In May 2026 the HL mean of 4.5 was slightly above the SL mean of 4.3, and HL had larger shares at grades 6 and 7. Who chooses each level may play a part, so this does not show that HL is easier.

IB subject statistics

IB Biology grade distribution and average grade, May 2026

By Michael Thompson - Head of Teaching Excellence; 15 years as an IB Coordinator

Published 5 October 2026Data: IB Diploma Programme provisional statistical bulletin, May 2026

Short answer: In May 2026, IB Biology students averaged 4.5 at HL (33,585 students) and 4.3 at SL (22,064). 7.4% of HL and 5.5% of SL students scored a 7, and the most common grade at both levels was 4.

This page summarises IB Biology results for the May 2026 session. The figures come from the IB's official statistical bulletin for that session. They are provisional, and a final version of the bulletin follows later in the year.

Biology is a large subject: 33,585 candidates sat it at Higher Level (HL) and 22,064 at Standard Level (SL). Below we look at the mean grade, how grades are spread, how HL and SL differ and how results compare with May 2025.

Key figures

Level	Students	Mean grade	Share of 7s	vs May 2025
HL	33,585	4.5	7.4%	no change
SL	22,064	4.3	5.5%	no change

Grade distribution, May 2026

Grade distribution, May 2026
Grade	Higher Level	Standard Level
1	0.9%	1.7%
2	5.1%	8.0%
3	19.5%	18.9%
4	24.9%	25.6%
5	23.2%	22.2%
6	17.2%	15.3%
7	7.4%	5.5%

Grade 1-7, % of studentsHigher LevelStandard Level

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What the mean grade tells you

The mean grade in May 2026 was 4.5 at HL and 4.3 at SL, on the IB's scale of 1 to 7. Both means sit in the middle of the scale, so a typical Biology candidate lands around grade 4 or 5 rather than at the top. Grade 4 is the most common single grade at both levels, with 24.9% of HL candidates and 25.6% of SL candidates. The session-wide mean diploma total was 30.9 points, but that figure covers all subjects plus the core, so it says nothing about Biology specifically.

How grades are distributed at HL and SL

All percentages below are shares of all candidates at that level, and any remainder received no grade. At HL the grades 1 to 7 were distributed as 0.9%, 5.1%, 19.5%, 24.9%, 23.2%, 17.2% and 7.4%. At SL the corresponding shares were 1.7%, 8%, 18.9%, 25.6%, 22.2%, 15.3% and 5.5%. SL has larger shares at grades 1 and 2, while HL has larger shares at grades 6 and 7. A grade 7 was reached by 7.4% of HL candidates and 5.5% of SL candidates. These are shares, not head counts, so the comparison is not affected by HL having more candidates. Why HL looks stronger is not something the data can show. One possibility is that students who choose HL Biology are often more committed to the sciences, but that is only a possible explanation.

Change compared with May 2025

The mean grades are unchanged from May 2025: 4.5 at HL and 4.3 at SL. Means are reported to one decimal place, so a very small shift could be hidden. Grade shares moved by small amounts as well: the share of 7s went from 7.2% to 7.4% at HL and from 5.9% to 5.5% at SL, and the largest single change was SL grade 3, down from 21.6% to 18.9%. Overall, Biology results look stable from one May session to the next.

What this means for subject choice and preparation

Biology is neither a subject where grade 7 is routine nor one where most candidates fall to the bottom. The spread is broad, with a large central group at grades 4 and 5, so steady work across the whole course matters more than any single topic. If you are weighing HL against SL, the slightly higher HL mean and the higher share of grades 6 and 7 are worth noting, but they do not mean HL is easier. HL candidates may differ from SL candidates in motivation and background. Choose the level that fits your university plans and the time you can give the subject, then use past papers and the mark schemes to practise exam technique.

Key takeaways

May 2026 mean grade: 4.5 at HL (33,585 candidates) and 4.3 at SL (22,064 candidates).
Grade 4 is the most common grade at both levels: 24.9% at HL and 25.6% at SL.
Grade 7 was reached by 7.4% of HL and 5.5% of SL candidates, while grade 1 was 0.9% at HL and 1.7% at SL.
Mean grades are identical to May 2025 at both levels, so scoring looks stable.
These figures are from the provisional bulletin; a final version follows later in the year.

Frequently asked questions

What was the mean grade in IB Biology in May 2026?: The mean was 4.5 at Higher Level and 4.3 at Standard Level, on a scale of 1 to 7. These figures come from the IB's provisional statistical bulletin for May 2026.
Did IB Biology grades change compared with May 2025?: The mean grades did not change: 4.5 at HL and 4.3 at SL in both May 2025 and May 2026. Because means are given to one decimal place, very small shifts would not show.
Is HL Biology scored higher than SL?: In May 2026 the HL mean of 4.5 was slightly above the SL mean of 4.3, and HL had larger shares at grades 6 and 7. Who chooses each level may play a part, so this does not show that HL is easier.