IB Grade Boundaries Explained (by Subject)

Every IB results day, the same question floods the chat groups: "What were the grade boundaries this year?" Students refresh forums. Parents ask what it all means. And almost nobody explains it in plain words.

This guide does. You'll learn what IB grade boundaries are, how the IB sets them, why they move every year, and what they tend to look like subject by subject. We'll keep the language simple and the numbers honest. It's written by Educifly's IB specialists, who have coached students through Diploma results since 2018.

Quick answer: what are IB grade boundaries?

IB grade boundaries are the mark cut-offs that decide which grade from 1 to 7 you get in each subject. Your exam papers and coursework are added up into a raw mark. The IB then sets a boundary for each grade. If your mark lands above the grade 7 boundary, you get a 7. If it lands above the grade 6 boundary but below the 7, you get a 6. And so on down to grade 1.

The key thing to know: these boundaries are not fixed. They change every exam session, and they differ for every subject and level. A grade 7 in one subject might need 70% one year and 66% the next. That sounds unfair at first. It's actually the system trying to be fair. We'll explain why below.

What is a grade boundary, in plain English?

A grade boundary is the lowest mark you can score and still earn a particular grade. Think of it like a high-jump bar. Clear the grade 7 bar, and you get a 7. Miss it by one mark, and you get a 6, even if you were one point away.

Here's a simple example. Imagine a subject is marked out of 100. The IB might set these boundaries:

In this example, you need 80 marks for a 7 and 70 for a 6. These numbers are made up to show the idea. Real boundaries shift each session, and they are almost never round numbers.

One more point. Your raw mark is not just one exam. It's all the parts of a subject added together — Paper 1, Paper 2, sometimes Paper 3, plus your Internal Assessment (IA, the coursework marked by your teacher). The boundary is set on that combined total.

How does the IB 1–7 scale work?

The IB grades every subject on a 1 to 7 scale, where 7 is the top grade and 4 is usually seen as a solid pass. Each number maps to a level of understanding, not a fixed percentage.

Here is what each grade broadly means:

You take six subjects in the Diploma. Each one gives you up to 7 points. Six 7s make 42 points. Then Theory of Knowledge (TOK) and the Extended Essay (EE) together add up to 3 bonus points. That's how the famous maximum of 45 points is built. If you want the full breakdown of how points add up, our guide to the IB scoring system walks through every step.

The IB grades are criterion-referenced. That's an important phrase. It means you're judged against a fixed standard of what a 7 looks like — not against other students. There's no bell curve. In theory, every student in the world could score a 7 if they all met the standard. That's different from systems that force a set percentage of top grades.

How does the IB set grade boundaries?

The IB sets grade boundaries after every exam session, in a meeting called the grade award. Marking comes first. Boundaries come last. This order is the whole secret to how the system works.

Here's the process, step by step:

1. Students sit the exams. Every paper is marked by trained examiners around the world.

2. The IB collects the raw marks. They now know how every student actually performed.

3. Senior examiners meet. This is the grade award. They look at the data and at samples of real student work.

4. They compare work to the grade descriptors. A grade descriptor is the official paragraph describing what a 7 should look like, what a 5 should look like, and so on.

5. They set the boundaries. They decide the lowest mark that matches each grade's standard for that specific paper.

Three things guide the decision: how hard the paper turned out to be, how students performed worldwide, and the fixed standard of what each grade should mean. The goal is simple. A 7 this year should mean the same as a 7 last year, even if the papers were different.

So the boundary is not a target set before the exam. It's a judgment made after, once the IB can see the full picture.

Why do IB grade boundaries change every year?

Boundaries change because exams are never exactly the same difficulty two years running, and the IB adjusts the cut-offs to keep each grade worth the same. This is the part students worry about most. It's also the part that protects them.

Picture two years of the same subject.

In Year One, the paper is fair and clear. Most students do well. To keep a 7 meaningful, the IB sets the grade 7 boundary at, say, 80%.

In Year Two, the paper is much harder. Even strong students struggle. If the IB kept the boundary at 80%, far fewer students would get 7s — not because they were worse, but because the paper was tougher. So the IB lowers the boundary, maybe to 73%. Now a student who truly understands the subject still earns their 7.

It also works the other way. If a paper turns out easy and scores rise everywhere, the IB raises the boundary. That stops an easy year from handing out grades that don't reflect real skill.

This is called statistical moderation, and it runs every session. The result: a grade 6 earned in 2026 should carry the same weight as a grade 6 earned in 2020. The numbers move so the meaning stays still.

One honest takeaway for students: you can't predict next year's boundary from last year's. Treat past boundaries as a rough guide, never a promise.

IB grade boundaries by subject: what they typically look like

Grade boundaries differ for every subject, and even for the same subject at Higher Level (HL) and Standard Level (SL). There is no single boundary that applies across the Diploma.

Some subjects tend to have higher grade 7 boundaries. Others tend to sit lower. The pattern depends on how the marks are spread and how demanding the papers are. Below is a general guide to the kind of range a grade 7 has needed in recent sessions across popular subjects. These are approximate bands, not official figures — every session is different.

Read these as "roughly where the bar has been," not as targets to bank on. The exact grade 7 cut-off for your session is only confirmed after the grade award.

Notice the spread. A 7 in HL Mathematics has often needed a lower percentage than a 7 in HL Economics. That doesn't mean Maths is easier. It means the marks are spread differently and the papers test in different ways. A low boundary usually signals a demanding paper where few students reach the very top marks.

Why are Maths grade boundaries often lower?

Maths grade boundaries are often lower because the papers are designed with hard, high-mark questions that very few students fully complete. In a subject like Economics, a strong essay can hit most of the marks. In Maths, the final questions are built to stretch even the best students.

So the marks spread out more. The top mark might be far below 100%. To keep a 7 fair, the IB sets the boundary lower to match where real top performance lands.

This is exactly why comparing boundaries between subjects can mislead you. A 65% grade 7 boundary in IB Maths and an 80% grade 7 boundary in Biology can represent the same level of mastery in each subject. Both are "the standard of a 7." The percentage just looks different.

If Maths is the subject keeping you up at night, that's common — it has some of the most feared papers in the Diploma. Targeted help with exam technique often moves a grade more than extra content ever could.

Are grade boundaries different for HL and SL?

Yes. Higher Level and Standard Level are separate qualifications, each with its own papers and its own grade boundaries. You can't read an SL boundary off an HL table, or the reverse.

HL covers more content and includes harder papers, sometimes an extra paper too. SL covers less and is pitched at a different depth. Because the papers differ, the IB sets a fresh set of boundaries for each.

The same is true inside Maths. Analysis and Approaches (AA) and Applications and Interpretation (AI) are four distinct routes once you split them by level: AA HL, AA SL, AI HL, AI SL. That's four separate boundary tables. If you want to understand which route suits you, our Math AA vs AI breakdown compares them side by side.

How do grade boundaries turn into your final IB score?

Grade boundaries convert your raw marks into a grade from 1 to 7 in each subject, and those six grades are then added up — plus up to 3 bonus points — to make your total out of 45. Boundaries are the bridge between marks and your headline score.

Here's the full chain:

1. Your papers and IA are marked. You get a raw mark for each subject.

2. Grade boundaries turn that raw mark into a subject grade (1–7).

3. Your six subject grades are added. Maximum 42.

4. TOK and the EE are graded A–E. Together they add 0 to 3 bonus points from a fixed matrix.

5. The total is your IB score out of 45.

To pass the Diploma you generally need at least 24 points, along with some other conditions about minimum grades and the core. We cover all of those rules in detail in our full scoring guide.

Want to see how your target grades add up? Our free IB Score Calculator lets you plug in subject grades and see your projected total in seconds.

What percentage do you need for a 7 in IB?

There's no single percentage for a 7 — it varies by subject, by level, and by exam session, but a grade 7 has commonly needed somewhere between roughly 65% and 85% of total marks. Anyone who gives you one fixed number is guessing.

Why the wide range? Two reasons we've already met. First, different subjects spread their marks differently, so the bar sits at different heights. Second, the IB moves the bar each session to match paper difficulty.

A safer way to think about it: aim well clear of the boundary, not right on it. If past grade 7 cut-offs in your subject have hovered near 75%, treat 80%+ as your working target. That cushion protects you if the boundary rises in a stronger year. It also takes the guesswork out of results day.

Where can I find the official IB grade boundaries?

Official IB grade boundaries are released to schools through the IB coordinator, not published openly on the IB website for students to download. Your fastest route is to ask your IB Diploma coordinator, who receives the full boundary tables after each session.

Be careful with random numbers online. Many sites post "boundaries" that are actually predictions, old sessions, or guesses copied from forums. They can be close, or they can be wrong. For anything that matters — like checking a remark decision — use the figures your coordinator holds.

A good habit: when you see a boundary online, ask three questions. Which session is it from? Which subject and level? Is it official, or a prediction? If you can't answer all three, don't rely on it.

How to use grade boundaries when you revise

Use grade boundaries to set a safe target mark, then build your revision around clearing it with room to spare. Boundaries are most useful before the exam, not just after.

Here's how strong students use them:

• Find your subject's recent boundary band. Get a rough sense of where the grade 7 (or your target grade) has been sitting.

• Add a cushion. Aim 5–10 marks above the typical boundary. This covers you if the paper is easy and the bar rises.

• Turn it into marks per paper. If you need 80 out of 100 overall, work out what that means on Paper 1, Paper 2, and your IA.

• Protect easy marks first. A clean IA and strong early exam questions bank marks before the hard questions arrive.

• Practise to the clock. Most lost marks come from running out of time, not from not knowing the content.

This is where focused coaching pays off. A specialist tutor can look at your past papers, spot exactly where marks leak, and turn a grade 5 into a grade 7 with the right technique. If you'd like that kind of help, you can book a free trial class with an Educifly subject specialist and see your weak spots mapped out in one session. For more on the mindset and method behind top grades, read our guide on how to score a 7 in IB.

Common mistakes students make about grade boundaries

The biggest mistake is treating last year's boundary as a guaranteed target for this year. Boundaries move, so a number that earned a 7 last May might not this May.

A few more traps to avoid:

• Aiming exactly at the boundary. One bad question and you slip a grade. Always aim above it.

• Comparing subjects by boundary. A lower boundary doesn't mean an easier subject. It usually means a harder paper.

• Trusting forum numbers. Unofficial boundaries float around every results season. Many are wrong.

• Forgetting the IA. Coursework marks feed into the same total as your exams. A weak IA drags your raw mark down before boundaries even apply.

• Ignoring HL vs SL. Reading an HL boundary when you sit SL (or the reverse) gives you the wrong target.

Get these right and grade boundaries stop being scary. They become a planning tool you control.

The bottom line

IB grade boundaries are simply the mark cut-offs for each grade from 1 to 7. The IB sets them after each session so that a grade means the same thing every year, whatever the paper threw at students. They change by subject, by level, and by session — so the smart move is to aim comfortably above the typical band, protect your coursework and easy marks, and check official numbers through your coordinator.

Understand the system, and results day holds far fewer surprises.

Frequently asked questions about IB grade boundaries

What are IB grade boundaries in simple terms?

IB grade boundaries are the lowest marks needed to earn each grade from 1 to 7 in a subject. Your exam papers and coursework are added into one raw mark. The boundary decides which grade that mark becomes. They are set fresh after every exam session, so the exact cut-offs change each year.

Do IB grade boundaries change every year?

Yes. The IB sets new boundaries after every exam session. This keeps each grade fair when papers vary in difficulty. If a paper is harder than usual, the boundary usually drops so students aren't penalised. If a paper is easier, the boundary can rise. You should never assume this year's boundaries will match last year's.

What percentage do you need for a 7 in IB?

There is no fixed percentage. A grade 7 has commonly required somewhere between roughly 65% and 85% of total marks, depending on the subject, the level, and the session. Maths often sits lower; essay subjects often sit higher. The safest plan is to aim above the typical boundary, not exactly on it.

Why are IB Maths grade boundaries lower than other subjects?

Maths papers include hard, high-mark questions that very few students complete fully. This spreads the marks out and pulls the top scores down. To keep a 7 fair, the IB sets the boundary lower to match where real top performance lands. A lower boundary reflects a demanding paper, not an easy subject.

Are HL and SL grade boundaries the same?

No. Higher Level and Standard Level are separate qualifications with different papers, so each has its own grade boundaries. You cannot use an HL boundary to judge an SL result, or the other way round. Always check the boundary for your exact level.

Who decides IB grade boundaries?

Senior examiners and subject specialists set them in a meeting called the grade award, held after marking is finished. They review real student work, compare it to official grade descriptors, and consider how hard the paper was and how students performed worldwide. Then they set the lowest mark that matches each grade.

Are IB grades based on a curve?

No. IB grades are criterion-referenced, not norm-referenced. You are measured against a fixed standard for each grade, not against other students. There is no set quota of 7s. In theory, every student could earn a 7 if they all met the standard for it.

Where can I find the official IB grade boundaries?

Official boundaries are sent to schools and held by your IB Diploma coordinator after each session. They are not posted openly for students to download. Ask your coordinator for the exact figures. Be cautious with numbers online, since many are predictions or from old sessions.

How do grade boundaries affect my final IB score?

Grade boundaries turn your raw marks into a subject grade from 1 to 7. Your six subject grades are added for up to 42 points, then TOK and the Extended Essay add up to 3 bonus points, for a maximum of 45. So boundaries are the step that links your exam marks to your overall score.

Can grade boundaries be used to predict my grade before results?

Only roughly. You can use recent boundary bands to set a safe target while you revise. But you cannot know the exact boundary for your session until after the grade award. That's why teachers tell you to aim several marks above the usual boundary, to stay safe if the bar moves up.

Do grade boundaries include Internal Assessment marks?

Yes. Your IA marks are added to your exam marks to make the subject's total raw mark. The grade boundary is then applied to that combined total. This is why a strong IA matters so much — it banks marks before the exam even begins and can lift you over a boundary.

What happens if I'm one mark below a grade boundary?

You receive the lower grade. The boundary is a hard line, so missing it by one mark drops you a grade. If you believe a paper was marked unfairly, you can ask your coordinator about a remark (an Enquiry Upon Results), which may move your mark above the boundary if marks were lost in error.