IB grade boundaries are the cut-off marks used to convert your combined assessment score into a final subject grade from 1 to 7. They are not fixed percentages, and they can differ by subject, level, examination session, and sometimes examination variant. The IB sets them after reviewing marked work, assessment difficulty, grade descriptors, examiner judgment, and statistical evidence.
This guide has IB grade boundaries explained from the beginning, including how component marks are weighted, why boundaries change, and how to use historical data without treating it as a prediction. It also explains why attempting real questions and reviewing the complete worked method is more valuable than repeatedly calculating hypothetical grades.
What is an IB grade boundary?
A grade boundary is the minimum overall mark required for a particular subject grade. If the boundary for a grade 6 were 67, for example, a final scaled mark of 67 would receive a 6, while 66 would fall into the grade below. The numbers in this example are hypothetical because actual boundaries depend on the subject and examination session.
A boundary table might look like this:
| Final scaled mark | Subject grade |
|---|---|
| 80–100 | 7 |
| 68–79 | 6 |
| 56–67 | 5 |
| 44–55 | 4 |
| 32–43 | 3 |
| 20–31 | 2 |
| 0–19 | 1 |
The table does not mean that every IB subject uses these ranges. It simply shows how consecutive ranges convert an overall mark into a grade. There is no universal rule that 70% equals a 7, or that 50% always equals a 4.
The IB describes DP results as standards-based, meaning achievement is judged against defined standards rather than each candidate's position in a simple global ranking. Statistical information is considered during awarding, but grades are not assigned using a fixed quota under which only a predetermined percentage of students may receive a 7.
How component marks become a final IB grade
Most DP subjects contain several assessment components. These may include written examination papers, an internal assessment, an oral, a performance, or other coursework, depending on the subject.
The process can be summarized as follows:
- Your work receives raw marks under the relevant markscheme or assessment criteria.
- Component marks are scaled so that each component contributes its official weighting.
- The scaled contributions are aggregated into an overall subject mark.
- The relevant overall grade boundaries convert that mark into a grade from 1 to 7.
According to the IB's assessment principles, the final subject grade is determined from the aggregation of component marks, not by averaging component grades. This distinction matters because two students with the same apparent component grades can have different marks within those grade ranges and therefore receive different final subject grades.
A simplified weighting example
Imagine a hypothetical subject with these components:
| Component | Raw result | Weight | Scaled contribution |
|---|---|---|---|
| Paper 1 | 52/80 | 30% | 19.50 |
| Paper 2 | 60/90 | 50% | 33.33 |
| Internal assessment | 20/24 | 20% | 16.67 |
| Combined total | 100% | 69.50 |
The student's performance on each component is converted into its weighted contribution. The combined result is then processed under the IB's aggregation procedures and compared with the subject's overall boundaries.
This is also why a strong internal assessment can compensate for a weaker examination paper, although only in proportion to its weighting. A component worth 20% cannot erase every weakness in components worth the remaining 80%.
The IB's official assessment-cycle overview provides a useful visual explanation of marking, scaling, grade awarding, quality checks, and enquiries upon results.
How the IB sets grade boundaries
Grade boundaries are established through a formal awarding process involving senior examiners and IB assessment staff. The evidence considered includes:
- the quality of candidates' work near possible boundaries
- published grade descriptors, which describe expected standards of performance
- examiner judgment about the demands of the assessment
- statistical evidence and comparisons with previous sessions
- information about the cohort and teacher feedback on examination papers
The IB's DP grade descriptors describe characteristics associated with different levels of achievement. Senior examiners examine candidate work to identify the lowest mark at which the characteristics of a particular grade are consistently demonstrated.
Certain key boundaries are determined judgmentally using the available evidence, while other boundaries may be calculated between them. This allows the IB to connect numerical marks to the intended meaning of each grade rather than applying an arbitrary percentage table.
New examination papers are used in each session, so examination boundaries are reconsidered. Boundaries for tasks that remain unchanged across sessions are generally expected to be more stable, although the IB reviews their continued appropriateness. The objective is to preserve the standard represented by a grade, not to preserve an identical cut-off mark.
Why IB grade boundaries change
No two examination papers are perfectly equal in difficulty. A paper may contain an unusually demanding data-response question, an unfamiliar application, or an essay prompt that candidates interpret less successfully than expected. A more accessible paper may produce the opposite effect.
Boundaries can therefore move to keep the meaning of grades reasonably comparable across sessions. If one paper is harder, a lower mark may demonstrate the same standard of achievement shown by a higher mark on an easier paper. This does not mean boundaries automatically fall whenever students feel that an examination was difficult.
The awarding team considers several forms of evidence together. Global performance statistics provide useful context, but they do not replace the review of candidate work against standards. As the IB's assessment information for students explains, grade awarding reconciles experienced examiner judgment, statistical comparisons, and expectations grounded in documented standards.
Boundaries may differ because of:
- the subject and assessment model
- HL or SL requirements
- the May or November examination session
- examination variants where applicable
- syllabus or assessment-model changes
For that reason, a boundary from an old syllabus or another level is not a reliable target for your own examination.
Boundaries, subject grades, and Diploma points
Each DP subject produces a grade from 1 to 7, with 7 being the highest. Six subject grades can therefore contribute up to 42 points. Theory of knowledge and the extended essay are graded separately and can contribute up to 3 additional core points, creating a maximum Diploma score of 45.
Grade boundaries determine the subject grades that enter this total. They do not replace the separate Diploma award conditions. Under the IB's current DP passing criteria, a candidate needs at least 24 total points and must satisfy additional requirements involving subject results, HL and SL totals, the core, CAS, and academic integrity.
It is also misleading to call grade 4 a universal IB “pass” for every purpose. The IB does not define an independent pass mark for every individual DP course. Universities and schools may impose their own minimum subject-grade requirements, often including particular HL grades.
How to use historical boundaries properly
Historical boundaries are useful for interpreting practice performance, but they cannot reveal the exact boundary for a future session. Use boundaries from the correct subject, level, syllabus, session, and examination variant whenever possible.
The RevisionDojo Grade Calculator can help convert representative practice marks into estimated subject grades using historical boundary data. Treat the result as a planning estimate rather than an official predicted grade.
A sensible approach is to:
- compare several recent applicable sessions rather than selecting the most favorable one
- calculate your weighted total using the correct component weights
- identify a realistic range for your target grade
- aim above that range to create a margin for timing errors and paper variation
- track progress using timed work rather than untimed homework marks
RevisionDojo's guide to how IB grade boundaries are calculated can support this comparison. The important strategic point is that boundaries are a measurement tool, not a revision method.
Turning boundary knowledge into exam marks
Knowing that you need approximately five more marks does not show where those marks will come from. The highest-leverage revision habit is to attempt an exam-style question independently, mark it honestly, and then review the complete worked method.
Use the following feedback cycle:
- Attempt a question under an appropriate time limit.
- Record every step, not only the final answer.
- Compare your response with the markscheme, criteria, or worked explanation.
- Identify whether you lost knowledge, method, interpretation, communication, or time-management marks.
- Redo the question without looking at the solution.
- Attempt a similar question several days later.
The RevisionDojo Questionbank supports targeted question practice, while Jojo AI can help explain why a method or response did not earn the expected credit. For supported subjects, per-question past-paper video solutions and worked explanations make the examiner-facing method visible rather than merely displaying a final answer.
As you approach the examinations, move from topic drills to complete timed sets. RevisionDojo's Predicted Papers and guidance on reviewing past IB papers efficiently can help you test timing, accuracy, and decision-making under realistic pressure.
Common mistakes when interpreting boundaries
Students commonly weaken their planning by making one of these assumptions:
- “Last year's boundary will be my boundary.” It is only historical evidence.
- “A 7 always requires a particular percentage.” Requirements vary substantially across subjects and sessions.
- “The IB grades on a simple curve.” Standards and candidate work are central to awarding, even though statistics are also used.
- “My component grades are averaged.” Weighted component marks are aggregated instead.
- “One mark never matters.” One scaled mark can matter greatly when the total is directly below a boundary.
- “A high IA guarantees my final grade.” Its influence is limited by its official weighting.
After results, candidates may be able to view a detailed subject result showing the scaled total mark, lower and upper grade boundaries, and marks required for a grade increase. According to the official IB assessment FAQ, access to this detail is provided at the discretion of the school's IB coordinator.
Conclusion
IB grade boundaries translate weighted assessment marks into subject grades from 1 to 7. They vary because the IB seeks to maintain comparable achievement standards even when assessment difficulty changes, so historical cut-offs should be used as estimates rather than promises.
Your most productive response is to build a secure mark margin through deliberate practice. RevisionDojo's Questionbank, Jojo AI feedback, timed papers, and per-question video solutions can help you attempt authentic questions, study the worked method, and convert mistakes into marks on the next attempt.
Sources and referenced URLs
- IB assessment FAQ and results information
- IB assessment principles and practices
- IB assessment-cycle overview
- Official DP grade descriptors
- IB student assessment and grade-boundary explanation
- Official DP passing criteria
- RevisionDojo IB Grade Calculator
- RevisionDojo guide to how grade boundaries are calculated
- RevisionDojo Mathematics AA Questionbank
- RevisionDojo per-question past-paper video solutions
- RevisionDojo Predicted Papers
- RevisionDojo guide to reviewing past IB papers
