The IB Diploma Programme reports achievement on a 45-point scale: up to 7 points in each of six subjects, plus up to 3 core points. A percentage usually reports how many marks a student earned out of those available, so it cannot be converted directly into an IB total without the relevant subject, assessment component, grade boundaries, and core results.
How the 45-point total is built
Each Diploma Programme subject receives a final grade from 1 to 7. Six subject grades can therefore contribute up to 42 points.
Students may earn up to 3 additional points through the combined assessment of Theory of Knowledge and the extended essay. Creativity, activity, service is also a Diploma Programme core requirement, but it does not add points to the total.
This creates the familiar maximum:
- Six subjects at 7 points each produce 42 points.
- Theory of Knowledge and the extended essay can add up to 3 points.
- The maximum total is 45 points.
The final diploma result also depends on meeting the programme’s requirements. A total alone should not be read without checking subject grades, core results, and any applicable conditions.
What criterion-referenced grading means
IB assessment measures student work against defined expectations for the course. Examiners award marks for demonstrated knowledge, reasoning, method, analysis, communication, or other qualities specified by the assessment.
The important comparison is between the student’s work and the published requirements. The aim is not to assign grades according to a fixed percentage of students who must receive each result.
A 6 therefore indicates that the work reached the standard associated with that grade in that subject and examination session. It does not mean the student answered 60% of the paper correctly, ranked in the top 6%, or earned the equivalent of an A under every school’s grading system.
Why a percentage and an IB grade can look inconsistent
A percentage may refer to several different things:
- the raw marks earned on one test
- a teacher’s weighted term grade
- an internal school reporting scale
- the percentage achieved across selected assessment components
- a predicted grade calculation
- a converted grade designed for another education system
These figures answer different questions. A student might earn 68% on a paper and receive an IB grade that looks stronger or weaker than a parent expects. That does not automatically indicate an error. The percentage must first be interpreted using the correct grade boundaries and assessment rules.
Grade boundaries connect mark totals to grades from 1 to 7. They can differ by subject, course level, assessment route, component, and examination session. For that reason, a universal table claiming that every percentage always equals the same IB grade can mislead families.
A practical example
Suppose a student receives 72 out of 100 on a school examination. The arithmetic is simple: the student earned 72%.
The interpretation requires more information. Was the paper written to IB standards? Did it cover the full course or only one unit? Did the teacher use official assessment criteria? Is 72% being compared with current boundaries for the correct subject and level? Does the school combine that paper with coursework, oral work, practical work, or other assessments?
Until those questions are answered, “72% equals an IB 6” is only an assumption.
This matters because Diploma Programme results can combine written examinations, externally assessed coursework, and school-based assessment. A single classroom percentage may reveal useful progress, but it may represent only one part of the eventual subject grade. The same caution applies when past papers cover only part of an assessment; our guide to syllabus assessment components explains how to check that coverage.
How parents should read an IB report
Start by identifying the kind of result shown. Look for labels such as raw mark, percentage, criterion score, predicted grade, semester grade, or final IB grade.
Next, confirm the programme. The 45-point total belongs to the Diploma Programme. PYP and MYP reports use their own curriculum and assessment structures, so families should avoid applying the Diploma Programme scale to them.
Then ask the school how the reported figure was calculated. Useful questions include:
- Which assessments contributed to this result?
- How were the components weighted?
- Were official or school-set grade boundaries used?
- Does the result represent one topic, a term, a predicted grade, or the full course?
- Which specific criteria need improvement?
Finally, compare like with like. Track a student’s performance in the same subject, at the same level, using comparable assessments. If a family must present results across IB, Cambridge, or AP systems, preserve the original grade and explain its scale instead of forcing every result into a percentage. The guide to showing academic progress across systems offers a practical format.
Turn the result into a study decision
The most useful question is not “What percentage is this IB grade?” Ask which assessment criteria cost the student marks and what practice would address them.
Bring the latest report, marked work, course level, assessment component, and teacher comments together. Choose one recurring gap, such as incomplete mathematical working, weak use of evidence, or poor time allocation. Set the next study block around that gap, then check progress with a comparable task rather than an unrelated percentage.
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