Choosing the right IB exam session and timezone
A plain-language guide to May and November sessions, timezone labels, syllabus changes, and fair historical comparisons.
IB Predict can show several boundaries for the same subject. That is normal: the IB may publish different boundaries for different examination sessions and paper variants. The safest choice is always the boundary that matches the information supplied with your paper or results. Ask your school coordinator when that information is unclear.
May and November sessions
The letter in a session code tells you when the examination took place:
- M25 means the May 2025 session.
- N25 means the November 2025 session.
May and November sessions do not contain the same group of students. A November boundary may be higher or lower than a May boundary, but that does not create a rule for the next session. Compare May with May and November with November when looking for a pattern.
Boundary timezone labels
Historical boundaries and mark schemes may use timezone labels to separate paper variants:
- TZ0: usually a worldwide or combined boundary.
- TZ1, TZ2, and TZ3: different paper variants where the published source separates them.
Do not assume that a TZ number always maps to one fixed region. The IB has changed examination delivery over time and introduced additional paper variants. Current examination schedules use exam zones A, B, and C to set local start times; those scheduling zones are not interchangeable with the TZ labels in historical boundary data.
The official IB examination schedule tells schools which schedule applies, and the IB recommends contacting your programme coordinator when you are unsure. The IB also explains that it introduced additional regional paper variants for May 2025.
Why timezones can have different boundaries
Different paper variants can contain different questions. The IB sets boundaries after reviewing how students performed on each examination version, so the minimum mark for a grade can differ slightly.
Do not select the timezone with the lowest boundary simply because it produces a higher predicted grade. That result would not describe the paper you actually sat.
Match the syllabus version
Some subjects change their assessment structure and content. Results from an older syllabus may not be a fair comparison, even when the subject name is unchanged.
On an individual subject page, use the syllabus selector and the “Current” label to confirm the course version. IB Predict limits many historical comparisons to sessions from the same syllabus, but you should still check this when interpreting an older table.
Pandemic-era sessions
Examinations and assessment arrangements changed during 2020–2022. Those results remain useful historical records, but they may not represent a normal examination cycle. Give more weight to recent sessions under the same syllabus.
A sensible comparison order
When choosing or comparing boundaries:
- Match your subject and level.
- Match your syllabus version.
- Select your actual May or November session.
- Match the TZ boundary variant supplied with your paper, mark scheme, or results.
- Use recent matching sessions for context, not as a guarantee of a future boundary.
For help reading your predicted grade, where-you-stand comparison, and grade outlook, see How to read your IB Predict results.