The Hardest and Easiest IB Subjects (2025 Data)
We ranked every major IB subject by its real average grade in the May 2025 exam session (202,102 students worldwide). Here is what it shows.
IB May 2025, at a glance
202,102 students · Average score 30.6 / 45 · Average grade 4.9 / 7 · Pass rate 81.9%
Source: IB Diploma Programme Statistical Bulletin, May 2025 (final).
What are the hardest IB subjects?
By average grade, Mathematics (4.4) and the Sciences (4.5) are the toughest subject groups. The lowest-scoring popular subjects in May 2025 were Maths AI SL, Sports & Exercise Science SL, and Physics SL. At Higher Level, History HL stands out as one of the lowest.
| Subject | Level | Avg grade |
|---|---|---|
| Maths AI | SL | 3.9 |
| Sports & Exercise Science | SL | 3.8 |
| Visual Arts | SL | 4.0 |
| Physics | SL | 4.2 |
| Biology | SL | 4.3 |
| History | HL | 4.4 |
What are the easiest IB subjects?
Language B (second language) subjects top the table, with Chinese B HL averaging 6.0 and English B HL 5.6. Among mainstream choices, Geography HL (5.3), Economics HL (5.2) and Global Politics HL (5.1) score highest. One caveat: many Language B students are already strong in that language, which lifts the average.
| Subject | Level | Avg grade |
|---|---|---|
| Chinese B | HL | 6.0 |
| English B | HL | 5.6 |
| Geography | HL | 5.3 |
| Economics | HL | 5.2 |
| Global Politics | HL | 5.1 |
| English A: Literature | SL | 5.1 |
How do the science subjects compare?
Here is a result that surprises most students: at Higher Level, Biology has the lowest average grade of the three core sciences. Physics HL (4.9) and Chemistry HL (4.8) both sit above Biology HL (4.5). The volume of content and the wording of exam questions make Biology deceptively hard to score in.
| Subject | HL avg | SL avg |
|---|---|---|
| Biology | 4.5 | 4.3 |
| Chemistry | 4.8 | 4.3 |
| Physics | 4.9 | 4.2 |
Studying IB Biology?
Biology HL has the lowest average of the three sciences. Our revision pack covers every topic across Themes A to D, built for the current syllabus.
Browse IB Biology resourcesDoes a low average grade mean a subject is harder?
Not entirely. An average grade reflects who takes the subject as much as the subject itself. A course chosen mainly by strong, motivated students will post a higher average even if the material is demanding. Use these numbers as a guide, not a verdict.
Should you choose IB subjects based on average grades?
No. Pick subjects you are genuinely good at and that your target universities require. A subject with a low average is not off-limits; it just means most students underperform without the right strategy.
What was the average IB score in 2025?
In the May 2025 session the global average was 30.6 points out of 45, with a mean grade of 4.9 and an 81.9% pass rate across 202,102 students. Anything above roughly 34 places you comfortably in the top third worldwide.
Data source: International Baccalaureate, Diploma Programme Statistical Bulletin, May 2025 (final). Figures are mean grades for subjects with 10 or more candidates. Last updated May 2026.