Current syllabus · first assessment 2025

IB · Biology · HL

IB Biology HL

Study the IB Biology HL syllabus with deeper coverage, topic practice, clear Concepts, Mastery progress and supporting Documents.

Question Bank Practice

Jump into a resource

Subject overview

IB Biology HL at a glance

Follow the live HL knowledge tree, including additional HL-only content and the topic groups and learning objectives for the course.

4
syllabus units
40
mapped topics
7
study tools

What you study in IB Biology HL

The HL course builds on the shared Biology foundations with greater breadth and depth across the same four organising themes and four levels of biological organisation.

Use the syllabus map to connect each HL objective to Concepts, Mastery and exam practice.

Explore the IB Biology HL syllabus

Follow the live HL knowledge tree, including additional HL-only content and the topic groups and learning objectives for the course.

IB Biology HL exam skills

Practise the command terms, data handling and extended reasoning used across IB assessment.

  • Follow command termsMatch the depth and structure of the response to the exact instruction.
  • Use data as evidenceRead units and uncertainty, identify patterns and support conclusions with values.
  • Build mark-efficient explanationsLink cause, evidence and subject vocabulary without repeating the prompt.

SourceCurrent IB subject guide and assessment objectives.

Know the exam

IB Biology HL assessment

First assessed in 2025, the HL course uses two external papers worth 80% and a scientific investigation worth 20%.

Paper / componentQuestionsTime% of grade
Paper 140 multiple-choice + 4 data-based questions75 marksPaper 1A multiple-choice questions and Paper 1B data-based or experimental-work questions.2 hours36%
Paper 2Section A: answer all · Section B: answer 2 of 380 marksData-based, short-answer and extended-response questions across the syllabus.2 hours 30 minutes44%
Scientific investigation1 scientific investigation24 marksAn individual open-ended investigation completed as a written report of up to 3,000 words.10 hours20%

SourceInternational Baccalaureate Organization (IBO) · Biology Guide · First assessment 2025

Exam results

Typical IB Biology grade boundaries

These reviewed raw-score ranges provide historical context. Exact boundaries vary by paper and examination session.

GradeTypical score bandHow to read it
436%Reviewed range across the referenced sessions
549%Reviewed range across the referenced sessions
662–63%Reviewed range across the referenced sessions
774–76%Reviewed range across the referenced sessions

Historical context only; always check the boundary for the exact paper and session.

Historical performance

IB Biology HL results at a glance

These figures show the candidate count, mean grade and grade distribution for the May 2023–2025 sessions. May 2025 was the first assessment of the current Biology course, so historical figures are context rather than a prediction.

Three-session average
4.4
mean score
Grade 7
6.8%
of candidates
Grade 6
16.6%
of candidates
Grade 5
22.6%
of candidates
Grade 4
27.2%
of candidates
Grade 3
17.6%
of candidates
Grade 2
7.0%
of candidates
Grade 1
0.9%
of candidates
SessionCandidatesMean7654321
May 2023 · Biology HL31,9124.416.3%16.5%24.0%27.2%17.8%7.1%1.1%
May 2024 · Biology HL32,1554.47.1%16.7%19.9%29.5%17.0%7.2%0.7%
May 2025 · Biology HL33,0794.47.0%16.6%24.0%25.0%18.1%6.7%1.0%

SourceIB statistical bulletins and reviewed Biology results records for the May 2023–2025 sessions.

HL includes additional syllabus content and requires greater depth across the same four organising themes. Its external papers are also longer than SL papers.

Paper 1 contributes 36%, Paper 2 contributes 44%, and the scientific investigation contributes 20% of the final subject grade.

Yes. The live HL knowledge tree includes the additional topics and learning objectives that are specific to Higher Level.