A grade boundary is not the same thing across every examination system. Some boards publish session-specific thresholds after marking. Some determine grade boundaries internally using examiner judgment and statistics. Some convert a composite score into a reporting scale. Singapore national examinations publish grading structures, but students should not assume unofficial fixed percentage cut-offs.
Cambridge International: published grade thresholds
Cambridge publishes grade threshold tables after each examination series. A threshold is the minimum mark needed for a particular grade in a component or syllabus combination. Thresholds can move from one series to another so that a grade represents a comparable standard even when a paper is easier or harder.
For some syllabuses, component marks are weighted before they are combined. The applicable threshold therefore depends on the candidate’s exact component combination. Cambridge publishes March, June and November threshold tables where those series apply.
IB: boundaries from marks to grades 1–7
IB combines weighted component marks into total scores, then divides those scores into grades 1–7. IB states that grade-boundary decisions use senior-examiner judgment, candidate work against grade descriptors and statistical evidence. Boundaries can therefore change between sessions.
AP: composite scores converted to 1–5
AP combines section scores into a composite score and then converts that composite to the 1–5 reporting scale. College Board states that AP cut points are based on research that connects AP performance with performance in comparable college courses. A score of 3, 4 or 5 is not produced by one universal percentage rule across all AP subjects.
Singapore national examinations
SEAB publishes the grading systems used for national examinations—for example G3/legacy O-Level grades A1 through 9, and A-Level grades A through U—but a student should not assume internet tables claiming a permanent raw-mark cut-off such as “75% always equals A1”. SEAB’s public 2026 explanation states which grades are considered passes, not a universal fixed raw-mark conversion table for every subject and year.
From 2027, SEC G1, G2 and G3 retain the grading structures corresponding to the preceding N(T), N(A) and O-Level standards respectively. The new SEC also publishes mappings between levels for progression calculations; those mappings are not the same thing as raw-mark grade boundaries.
Why thresholds move
- Paper difficulty can vary.
- Cohort evidence can vary.
- Assessment models can change.
- Boards aim to maintain standards across different examination sessions.
- Component weightings can affect the final total differently.
How students should use historical boundaries
- Use them to understand approximate historical performance, not to predict your exact future grade.
- Always match the correct syllabus, component combination and exam session.
- Do not lower your revision target to last year’s minimum threshold.
- Train for secure mathematical performance with margin for paper variation.
Official grading-source links | checked 28 September 2026
- Cambridge IGCSE grade threshold tables — thresholds are published after each series and can vary with paper demand and component combination.
- Cambridge Understanding Results — marking, weighting and threshold-setting are separate stages.
- IB grade-boundary research — grade award uses multiple evidence sources and is carried out for each examination session.
- College Board About AP Scores — weighted section scores form a composite score which is translated to the 1–5 scale.
- AP score setting and scoring — current score standards use evidence-based standard setting rather than one universal raw-percentage table.
- SEAB Secondary Education Certificate — publishes G1/G2/G3 grading structures and progression mappings; these mappings are not raw-mark grade boundaries.
Maintenance rule: attach board, syllabus, component combination and examination session to any historical threshold. Never publish a future threshold as though it were known before the board completes marking and grade award.
Official sources checked 28 September 2026: Cambridge International grade-threshold and results guidance, IB grade-award research, College Board AP score-setting guidance and SEAB SEC grading information. Historical thresholds remain descriptive evidence for the named session, not future promises.
World Mathematics route: return to the World Mathematics Atlas for the wider map behind this grading reference: examinations, curricula and current board rules.
Grade boundaries and thresholds: read them as board-specific evidence, not universal conversions
A grade boundary belongs to a specific assessment system
SEAB/Singapore-Cambridge, Cambridge International, IB and AP use different assessment structures and reporting systems. A number from one cannot be converted mechanically into a grade in another.
Historical thresholds are descriptive, not promises
Where a board publishes thresholds or boundaries, they refer to a particular examination session or assessment cycle. Future boundaries can change with paper difficulty and board procedures.
Raw marks and scaled marks are different concepts
Some systems combine components, weighting or scaling before a final grade is awarded. Always identify which kind of mark a published table uses.
School cut-offs are not examination grade boundaries
Internal promotion rules, prelim grade bands and admission cut-offs serve different purposes. Do not merge them into one table simply because all use percentages.
IB boundaries are subject/session specific
IB grade boundaries can vary by subject, level and session. Internal assessment and external components also have their own structures.
AP scores are not percentage grades
AP reports scores on its own scale after College Board’s scoring process. A classroom percentage is not a direct AP score conversion.
Use boundaries after learning diagnosis, not before
A student should first identify knowledge and execution gaps. Chasing an estimated threshold can encourage strategic neglect of content that later papers test differently.
For parents
Ask what the reported number actually represents: raw paper mark, weighted component, school grade, predicted grade or final board grade. This prevents false comparisons.
For tutors
Keep board/year metadata attached to every threshold table. Remove or date stale figures rather than presenting them as timeless.
Safe comparison rule
Compare curriculum coverage, assessment structure and published grade systems separately. Do not publish a cross-board table claiming that one exact percentage ‘equals’ another board’s grade without an official conversion.