How the IB marks your work: exams, IAs, the EE and TOK

Every IB subject grade is built from two kinds of assessment. External assessment (your exam papers, plus any coursework sent away) is marked by IB examiners who have never met you. Internal assessment (the IA) is marked by your teacher, and the IB then re-marks a sample from your class and can move everyone's marks up or down. Your weighted total across all components is converted to a grade from 1 to 7 using grade boundaries that senior examiners set after each exam session.

The Extended Essay and TOK work differently: each gets a letter from A to E, and the two letters together give you up to 3 extra points.

What is the difference between external and internal assessment?

External components are marked by the IB. Internal components are marked at school and moderated by the IB. Every subject guide fixes how much each component is worth, and the split varies more than most students expect.

In the core, the Extended Essay is externally assessed. TOK is split: the essay is marked by IB examiners and makes up two thirds of the TOK grade, and the exhibition is marked by your teacher, moderated, and makes up the other third. CAS is not assessed and carries no points, but you need to complete it to get the Diploma.

Who marks IB exams?

IB examiners. To apply, an examiner needs a degree in the subject or a related one and at least a year of experience teaching it to students aged 16 to 19, and anyone no longer teaching must have taught or examined within the last three years.

The IB's assessment guide for examiners (2016 edition) describes how the marking is kept consistent:

• Most externally assessed components are marked on screen. Your script is split into groups of questions, so different examiners may mark different parts of your paper.
• The principal examiner sets the standard. After the exam, the principal examiner and senior examiners agree definitive marks for a set of real scripts and add clarifications to the markscheme, such as extra answers to accept.
• Examiners must qualify before live marking. They mark practice scripts, compare their marks with the definitive ones, and then have to land within a set tolerance on a qualification set.
• Hidden check scripts keep them on track. Already-marked "seed" scripts are mixed into live marking. An examiner who drifts out of tolerance is stopped and retrained, and one who keeps drifting is suspended.

As of February 2026, the IB says it keeps human examiners for marking and is exploring AI only as a quality-control check, with humans following up. Separately, it is introducing on-screen exams in a small number of subjects from 2026, run alongside paper exams. Your coordinator will tell you if any of your papers are affected.

What is the difference between a markscheme and markbands?

These are the two ways IB work gets marked, and they reward different habits.

A markscheme lists the creditable points for a question. Each mark needs a specific, correct point, and a vague answer earns nothing even if it is roughly right. In maths, markschemes separate method marks from accuracy marks, so working that shows a correct method can score even when the final number is wrong. Short-answer questions and calculations are marked this way.

Markbands describe levels of quality. The examiner reads the whole response, picks the band that fits it best, then places it within that band. Markbands are used for the IA criteria, the Extended Essay, TOK, and longer written answers. Two verified examples:

• In ESS Paper 2, the final part of each Section B essay (9 of its 20 marks) is marked with markbands; the rest uses a markscheme.
• The Extended Essay is marked on a best-fit basis and marked positively: the examiner credits what is there, and the top band does not require a flawless essay.

In practice: for markscheme questions, write one distinct, precise point per mark. For markband answers, the structure of your argument and the quality of your judgement matter as much as the facts. Our guide to how IB mark schemes award marks goes through both, with examples.

How is the IA moderated?

Your teacher marks every IA in the class against the criteria. The school then uploads a sample chosen to cover the range of marks the teacher gave, and an IB moderator marks that sample.

The moderator is not looking for a different opinion on each piece of work. The question is whether the teacher's marking is in line with the IB standard. If it is, the marks stand. If it isn't, the IB works out an adjustment from the gap between the teacher's marks and the moderator's marks, and applies it to every student that teacher marked, not just the ones in the sample.

Two practical consequences. First, aim to earn the top band on the criteria as written, not as your class interprets them; read the criteria yourself (our science IA criteria guide and Maths IA criteria guide put them in plain words). Second, the comments your teacher gives on your one draft are your best preview of the moderator's view, so act on all of them.

How are IB grade boundaries set?

Marks become grades at grade awarding, a meeting of senior examiners and IB staff shortly before results are issued. They decide the minimum mark for each grade using several sources together: their professional judgement of real scripts, statistics on how candidates performed, the grade descriptors for the subject, and feedback from teachers about the paper.

• Boundaries move with difficulty. A hard paper usually gets lower boundaries and an easy one higher boundaries, so the standard for a 7 stays the same while the mark needed moves.
• Every session has its own exam boundaries, and different time-zone versions of the same paper can have different ones.
• Coursework is treated differently. The examiner guide says IA boundaries are set when a course starts and reviewed afterwards, rather than reset each session, because the task does not change.

Your coordinator can access the boundaries for past sessions. We explain how to read old boundaries without over-trusting them in IB grade boundaries explained.

How do the components combine into a 1 to 7?

Each component is scaled to its weighting, the scaled marks are added, and that subject total is converted to a grade using the subject boundaries. You do not need a particular grade on each paper; a strong component can make up for a weaker one.

The weighting has a consequence most students never work out: a mark is not worth the same on every component. Take Biology, using the official marks and weightings:

At HL, one IA mark is worth about 1.7 marks on Paper 1 and 1.5 marks on Paper 2. Do the same sum for your other subjects with the numbers in your subject guide; it tells you where an extra hour of work buys the most.

How do the Extended Essay and TOK grades work?

Both are graded A to E rather than 1 to 7.

• Extended Essay: from May 2027 it is marked out of 30 on five criteria (out of 34 on the old model, last used in November 2026). Senior examiners set the A to E boundaries each session using fixed grade descriptors. No boundaries for the 30-mark model exist yet; see EE grade boundaries for what is known.
• TOK: the essay and the exhibition are each marked out of 10 by global impression, with the essay counting twice as much. The combined result becomes a single A to E grade.

Your two letters are then read off a matrix for 0 to 3 core points:

An E in either one means no Diploma, whatever your points total. The other failing conditions are in IB points explained.

When and how do you get your results?

Results for the May session are released in early July and for the November session in early January. You log in to the IB candidate website with a personal code and PIN from your coordinator. If you sit in May 2027, expect your results in early July 2027; the IB confirms the exact date and time nearer the session.

The IB will send your results to up to six universities free of charge, but only if your coordinator submits the request before results are issued. Give your coordinator the list in spring.

Can you get an IB exam re-marked?

Yes, through an enquiry upon results (EUR). The rules:

• Only your school can request it, after results are out. You cannot contact the IB yourself.
• Fees apply. For a re-mark of externally assessed work, the fee is refunded if your grade changes.
• Your mark can go down as well as up, so the school needs your written consent. The re-mark is normally done by a different, senior examiner.
• There are different categories. Category 1 is a re-mark of externally assessed work. Category 2 returns your marked work to the school without re-marking it. Category 3 re-moderates the school's IA sample, is only possible when the teacher's marks were reduced significantly, and cannot lower marks.
• The deadline is around mid-September for the May session and mid-March for November. Check the exact date with your coordinator.

Before results come out, the IB also runs its own checks. The examiner guide describes re-checking candidates whose result is two or more grades below their prediction and who are only a mark or two short of the next grade. That check confirms marks are right; it does not search for extra ones.

Whether a re-mark is worth it depends on how close you are to the boundary. If you are one or two marks short of a grade that matters for a university offer, ask your coordinator for your component marks and the session boundaries before you decide.