IB Biology HL 2025 Grade Boundaries Guide (What You Need for a 7)

Refreshing your inbox for grade boundary leaks instead of actually revising? If you are googling “IB Biology HL 2025 grade boundaries” or “what mark do I need for a 7 in Bio HL,” you are not alone.

Grade boundaries feel scary, but they are just the lines that turn your total mark into a 1 to 7 grade. They matter a lot for predicted grades, university offers that ask for “6 in HL Biology,” and for planning how hard you need to push in the final months.

The good news: the latest May 2025 boundaries for IB Biology HL are very close to 2024 and 2023. So past papers and older grade boundaries are still a reliable guide, not random numbers from another era.

Below is a clear, calm breakdown of what you need to know, using the latest 2025 data and simple comparisons with 2023 and 2024.

IB Biology HL 2025 Grade Boundaries at a Glance (Marks for 1 to 7)

For May 2025 IB Biology HL, the final grade boundaries out of 100 are:

Grade	Mark range (out of 100)
7	79 – 100
6	64 – 78
5	50 – 63
4	35 – 49
3	23 – 34
2	13 – 22
1	0 – 12

These are scaled totals for the whole subject, not just one paper.

Put simply:

• A 7 means you are scoring close to 80 percent or higher overall.
• A 6 means solid, consistent work, usually in the mid 60s or low 70s.
• A 5 means a good pass with clear understanding but some gaps.
• A 4 is a pass, but with larger holes in knowledge or exam skills.
• 3 and below signal that big areas of the syllabus are weak or missing.

Exact IB Biology HL May 2025 grade boundaries (out of 100)

Here is the same data written in sentence form, which can feel easier to digest.

• To get a 7 in IB Biology HL in May 2025, you need between 79 and 100 marks out of 100.
• To get a 6, you need between 64 and 78 marks out of 100.
• To get a 5, you need between 50 and 63 marks out of 100.
• To get a 4, you need between 35 and 49 marks out of 100.
• To get a 3, you need between 23 and 34 marks out of 100.
• To get a 2, you need between 13 and 22 marks out of 100.
• To get a 1, you score between 0 and 12 marks out of 100.

These numbers come from the official May 2025 boundaries, just converted to a simple “out of 100” scale so students can think in percentages.

What these marks mean for your final IB Biology HL grade

A key point: these marks are for your total Biology HL score. That includes:

• Paper 1 (multiple choice)
• Paper 2 (structured and extended response)
• Paper 3 (data and practical questions)
• Internal Assessment (IA lab investigation)

All of those pieces are weighted, then scaled into a final total out of 100. The grade boundaries are applied to that final total.

A few quick examples:

• If you are on track for 65 out of 100, you sit comfortably in the 6 band. Many university courses that ask for “6 in HL Biology” would count this as meeting the requirement.
• If you are tracking at 78, you are at the very top of a 6, only one mark below a 7. A small gain in Paper 2 or your IA could push you over.
• If you are around 51, you are in the 5 band. That is a solid pass, but if your course or country often expects a 6 in HL sciences, there is still room to grow.

One helpful way to use these boundaries is to plug your current test scores and IA mark into a free IB Diploma score calculator to see how close you are to each band.

How IB Biology HL 2025 Grade Boundaries Compare to 2024 and 2023

Here is the part many students find calming.

For IB Biology HL, the grade boundaries in 2023, 2024, and 2025 are almost identical. The key line for a 7 stayed at 79 out of 100 in all three years. The lines for 6, 5, 4, 3, 2, and 1 also stayed the same.

That means:

• Past papers from 2023 and 2024 are still a reliable guide for 2025.
• If you used 2023 or 2024 boundaries during mock exams, you do not need to “relearn” new numbers.
• The IB has kept the meaning of each grade stable over this period.

The final official boundaries turned out to be closer to 2023 and 2024, which helps keep things consistent for students.

Grade 7 to 1 compared over 2023, 2024, and 2025

Across 2023, 2024, and 2025, IB Biology HL grade boundaries (out of 100) line up as:

• 7: 79 to 100
• 6: 64 to 78
• 5: 50 to 63
• 4: 35 to 49
• 3: 23 to 34
• 2: 13 to 22
• 1: 0 to 12

These bands match all three years.

The key takeaway: if you were using past papers with past grade boundaries, they are still a very good guide for 2025.

What stable grade boundaries tell you about IB Biology HL difficulty

If grade boundaries stay the same over several years, it usually means:

• The overall difficulty of the papers is similar.
• Student performance worldwide is also similar.
• The exam board has adjusted slightly behind the scenes to keep a 7 in 2025 equal in value to a 7 in 2023.

This does not mean every question in every paper feels the same. One year might have a nasty data question, another year might have a tricky essay. But on average, the total difficulty and performance balance out.

The IB explains this balancing process in its official IB Diploma statistical bulletin, which shows how results compare across sessions.

How IB Biology HL Grade Boundaries Are Decided (And Why They Change Slightly)

Students often ask:

• “Will they lower the boundaries if the exam is hard?”
• “Is there a curve?”
• “Do they decide the boundaries before we even sit the exam?”

The real answer is more boring and more fair than rumors online.

Each exam session, the IB looks at how thousands of students perform, how hard the papers were, and how the results compare to past years. Then experienced examiners set grade boundaries so that a 7 still means top level work, and a 4 still means a pass, no matter the year.

What the IB looks at when setting Biology HL grade boundaries

In simple terms, exam teams look at:

• Difficulty of the papers
  If Paper 2 has a very strange data set or tricky essay choices, students might score lower.
• How students did worldwide
  They look at full mark distributions from thousands of candidates, not just one school.
• Comparisons with past years
  If students with similar ability in 2023 and 2025 get very different raw marks, that is a sign the paper was easier or harder.
• Student work around key grades
  Senior examiners read real scripts near the 7, 6, 5 lines and ask, “Does this still feel like a 7?”

A simple way to think about it: boundaries help keep meaning stable. A 7 in 2025 should look like the same quality of work as a 7 in 2023, even if the questions are different.

Why boundaries can go up or down if an exam is easier or harder

Boundaries are not fixed forever. They move a little when needed.

• If a paper is very hard, many students get lower marks than usual. To keep the meaning of each grade the same, the boundary for a 7 might move down. For example, for a very hard session, a 7 might start at 75 instead of 79.
• If a paper is easier than usual, more students score high marks. In that case, the boundary for a 7 might move up, since a 7 is meant to show top performance, not just an easy exam.

Students are not compared to a fixed number every year. They are compared to the paper in front of them and to each other across the world.

This is why prediction sites and Reddit threads can only guess before the official boundaries come out. The real numbers depend on how the full group of students actually did.

What to Expect for IB Biology HL November 2025 Grade Boundaries

The November session often has fewer candidates than May, but the process for setting boundaries is the same.

Given that IB Biology HL boundaries for May 2023, May 2024, and May 2025 are identical, it is reasonable to expect that November 2025 will sit very close to the same lines, unless the exam is clearly easier or harder than normal.

Some prediction pages explain these patterns across years. They also show how large shifts are rare when a subject has already settled after syllabus changes.

Likely November 2025 range for a 7, 6, and 5 in IB Biology HL

No one outside the IB knows the exact November 2025 boundaries yet. But based on the 2023 to 2025 pattern, a sensible estimate looks like this:

• Grade 7: likely to start in the high 70s (around 75 to 79).
• Grade 6: likely to sit in the mid 60s to high 70s.
• Grade 5: likely in the low 50s to low 60s.

Treat this as an informed estimate, not a promise. The final numbers will depend on the actual paper and global performance.

For planning, use the May 2025 lines, then aim a few marks higher to stay safe.

How to plan your study with changing grade boundaries in mind

Boundaries move a little. Your plan should not.

A few simple, practical ideas:

• Aim above the line
  If a 7 starts at 79, set a personal goal of 82 to 85. That way you have room for a bad day or a weird question.
• Spread your effort across all components
  Do not rely only on Paper 2. Your IA and Paper 1 can lift your total. A slightly better IA can “buy back” mistakes in one paper.
• Use boundaries to track progress, not to panic
  Every few weeks, total your past paper scores, convert to a mark out of 100, and see which band you are in. Treat it like checking your heart rate during a run, not like checking final results.
• Do not count on boundaries dropping
  Hoping for “a very hard exam so the boundaries will save me” is risky. It is far safer to plan as if the 7 boundary will stay at 79 or higher.

Study Strategy: How to Hit Your Target Grade in IB Biology HL 2025

Knowing the numbers is only helpful if it changes how you work.

Most students reading about grade boundaries are aiming for a 5, 6, or 7. The ideas below focus on those bands and on turning abstract boundaries into concrete daily actions.

Turn grade boundaries into a clear score goal for yourself

Start with your target grade, then set a safe score goal.

Example: you want a 6 in Biology HL.

• Official line for a 6: 64 to 78.
• Safe personal goal: around 68 to 72 or higher.

Now break that into parts. You do not need perfect math here, just rough targets:

• Paper 1 (20 percent): Aim for around 70 percent.
• Paper 2 (36 percent): Aim for around 68 to 70 percent.
• Paper 3 (24 percent): Aim for around 65 to 70 percent.
• IA (20 percent): Aim for at least 70 percent.

If those pieces are close to your targets, your scaled total should sit safely in the 6 band, with a chance of reaching a 7 if some parts go better than expected.

Smart practice with past papers and mark schemes

Since 2023, 2024, and 2025 boundaries are stable, past papers from these years are almost like practice runs for your own exam.

A simple, effective routine:

1. Pick one full paper
   Start with Paper 1 or Paper 2 from a recent session.
2. Sit it in exam conditions
   Use the real time limit. No notes, no distractions, phone away.
3. Mark it with the official mark scheme
   Mark yourself strictly. Give marks only when your answer matches the key idea.
4. Convert to a total out of 100
   Combine scores from different practice papers, then compare your total to the 2025 boundaries.
5. Track scores over time
   Keep a simple spreadsheet or notebook: date, paper, percent, rough total band. You want to see a trend toward your target band.

This process does two things. It trains you to think like an examiner, and it makes the grade boundaries feel less random, because you keep seeing how your scores map to them.

Common mistakes that keep students below the 7 boundary

Many students sit at 74 to 78 percent, just under a 7. Often the problem is not knowledge, but habits. Here are frequent issues and quick fixes.

• Missing command terms
  Problem: answering “describe” when the question says “explain” or “evaluate.”
  Fix: highlight the command term in every question during practice. Say it out loud before you plan your answer.
• Not linking structure to function
  Problem: listing facts about a structure without saying what it does or why.
  Fix: force yourself to use the phrase “this allows” or “this leads to” when writing about structures, such as villi or alveoli.
• Weak data analysis in Paper 2 and 3
  Problem: copying data from a graph instead of interpreting trends.
  Fix: in practice, always include phrases like “as X increases, Y decreases” and add one possible biological reason.
• Poor time management
  Problem: spending too long on early questions, then rushing the final big ones.
  Fix: write a time check on the front page of each practice paper, for example “Question 1 done by 20 minutes, Section B done by 1 hour.”
• Leaving blanks
  Problem: skipping hard questions and never coming back.
  Fix: put a clear star next to questions to return to, then leave at least 10 minutes at the end to fill gaps with your best guess.

Each small fix can add one or two extra marks per paper. Across three papers, that can be enough to move from the top of a 6 into the 7 band.

Conclusion

For May 2025 IB Biology HL, your whole grade comes from a total out of 100, with a 7 starting at 79 marks. The rest of the scale, from 6 down to 1, follows the stable bands used in 2023 and 2024 as well.

That stability is good news. It means past papers, past grade boundaries, and your mock results are all meaningful guides, not old data you have to ignore. Use the boundaries as a tool to set clear goals, not as a source of panic.

Pick a target mark for the week, choose one past paper, and start a simple tracking sheet. With steady practice and smart use of the grade boundaries, you can turn “What if I fail Bio HL?” into “Here is how I am climbing toward my 6 or 7.”