IB grade boundaries are the minimum weighted marks needed for grades 1 to 7 in a particular subject, level, and examination session. They are not fixed percentages, and there is no universal score that guarantees a 7 across every IB subject.
Your examination and coursework marks are combined according to the subject's assessment weightings. The resulting scaled total mark is then compared with the boundaries for that session. Because boundaries are finalized after marking, students should use previous boundaries as planning evidence, not as guaranteed future cut-offs.
How IB grade boundaries are set
The IB distinguishes between marking and grading. Marking determines how many marks an answer earns under a markscheme or assessment criteria, while grading interprets the overall quality represented by those marks.
According to the IB's assessment guidance for students and parents, senior examiners and IB staff consider:
- The quality of candidate work against published grade descriptors
- Expert examiner judgment
- Statistical evidence from the session
- The difficulty and demands of the assessment
- Feedback submitted by teachers about the examination
The IB is standards-referenced, not simply norm-referenced. This means it does not automatically decide that a fixed percentage of candidates must receive each grade. Boundaries are adjusted to preserve a comparable standard when one examination is more or less demanding than another.
From raw marks to a final subject grade
Suppose a fictional subject consists of two examinations and an internal assessment. The calculation could work as follows:
| Component | Raw result | Assessment weighting | Contribution to scaled total |
|---|---|---|---|
| Paper 1 | 42/60 | 30% | 21.0 |
| Paper 2 | 58/80 | 50% | 36.25 |
| Internal assessment | 17/20 | 20% | 17.0 |
| Overall | : | 100% | 74.25 |
The candidate's final result would normally be reported as a whole scaled mark and compared with the session's overall subject boundaries. Component marks therefore do not simply get added together when the components have different maximum marks and weightings.
Most importantly, a candidate's final subject grade comes from the aggregation of component marks, not from averaging component grades. A grade 6 on one paper and a grade 7 on another does not automatically produce 6.5 or guarantee a final 7.
Boundary tables by year and grade
A single IB boundary table covering every subject would be misleading. Exact boundaries differ by subject, SL or HL, assessment route, examination session, and sometimes paper variant or timezone.
| Boundary information | What it tells you | How to use it |
|---|---|---|
| Grade 7 lower boundary | Minimum scaled mark awarded a 7 | Treat recent figures as a target baseline |
| Grade 6 lower boundary | Minimum scaled mark awarded a 6 | Measure how much improvement is needed |
| May session boundary | Standard applied in that May examination | Compare primarily with other May sessions |
| November session boundary | Standard applied in that November examination | Do not assume it matches the May boundary |
| Earlier syllabus boundary | Result under an older assessment model | Use cautiously if components have changed |
RevisionDojo's IB grade boundaries database allows students to select the relevant year, session, subject, level, and available timezone. The IB Grade Calculator can then convert representative practice marks into an estimated subject grade and diploma total.
This guide should be reviewed after each May and November results release because new session data may change the historical range.
What you need for a top grade
A grade 7 is the highest subject grade, but the required percentage varies significantly. Do not rely on claims such as “80% is always a 7” or “70% is enough in every science.”
A safer revision strategy is to:
- Check several recent boundaries for the correct subject and level.
- Exclude sessions using a substantially different syllabus or assessment model.
- Identify the highest recent grade 7 boundary.
- Add a practical buffer of several scaled marks.
- Test that target across multiple timed papers.
The buffer matters because practice marking is imperfect and future boundaries are unknown. Use the Questionbank and timed practice workflow to produce several data points rather than judging readiness from one strong paper. Jojo AI can help identify markscheme errors, while full mock exams test whether the target remains achievable under time pressure.
Subject grades are not the same as diploma points
Each of the six DP subjects contributes 1 to 7 points, giving a maximum of 42 subject points. TOK and the extended essay can add up to 3 core points, producing the maximum diploma total of 45.
Under the IB's current diploma passing criteria, earning 24 points alone is not sufficient. Candidates must also satisfy conditions involving CAS completion, HL and SL totals, low subject grades, and TOK and EE results.
Results, boundaries, and re-mark decisions
Detailed results may show your scaled total mark, lower and upper boundaries, and marks required for the next grade. Access to this detailed view is controlled by the school's coordinator.
If you are close to the upper boundary, discuss an Enquiry Upon Results, or EUR, with your coordinator. A Category 1 EUR re-marks externally assessed components and can raise, confirm, or lower the result, so closeness alone does not guarantee a change. RevisionDojo's guide to one-mark re-mark decisions explains the risk more fully.
Conclusion
IB grade boundaries translate weighted subject marks into grades while accounting for assessment difficulty and stable academic standards. They vary by subject and session, so historical figures should guide revision without being treated as promises.
Aim above the highest relevant recent boundary, practise under timed conditions, and track weighted totals rather than isolated paper percentages. RevisionDojo's Grade Boundaries database, Grade Calculator, Questionbank, mock exams, and Jojo AI can support that evidence-based approach.
Sources and referenced URLs
- IB assessment guidance for students and parents
- IB assessment and results FAQ
- Official IB grade descriptors
- Official IB Diploma passing criteria
- RevisionDojo IB Grade Boundaries
- RevisionDojo IB Grade Calculator
- How RevisionDojo explains grade-boundary calculations
- RevisionDojo guide to predicting IB scores from timed evidence
- RevisionDojo guide to one-mark re-mark decisions
