IB Computer Science 2027 syllabus: every topic and what changed
The 2027 IB Computer Science syllabus has two themes. Theme A, "concepts of computer science", covers hardware, networks, databases and machine learning and is examined in Paper 1. Theme B, "computational thinking and problem solving", covers programming, object-oriented programming and (HL only) abstract data types and is examined in Paper 2, where every student writes code in Java or Python.
Every topic in the 2027 syllabus
“Mixed” means most of the topic is for everyone, with some HL-only points. Levels are as reported by public sources.
| Code | Topic | Level | On this site |
|---|---|---|---|
| A1.1 | Computer hardware and operation | Mixed | 5 questions |
| A1.2 | Data representation and computer logic | SL and HL | 4 questions |
| A1.3 | Operating systems and control systems | Mixed | 3 questions |
| A1.4 | Translation | HL only | 2 questions |
| A2.1 | Network fundamentals | Mixed | 4 questions |
| A2.2 | Network architecture | Mixed | 3 questions |
| A2.3 | Data transmissions | Mixed | 2 questions |
| A2.4 | Network security | Mixed | 3 questions |
| A3.1 | Database fundamentals | SL and HL | 4 questions |
| A3.2 | Database design | SL and HL | 3 questions |
| A3.3 | Database programming | Mixed | 4 questions |
| A3.4 | Alternative databases and data warehouses | HL only | 1 questions |
| A4.1 | Machine learning fundamentals | SL and HL | 6 questions |
| A4.2 | Data preprocessing | HL only | 3 questions |
| A4.3 | Machine learning approaches | HL only | 4 questions |
| A4.4 | Ethical considerations | SL and HL | 2 questions |
| Code | Topic | Level | On this site |
|---|---|---|---|
| B1.1 | Approaches to computational thinking | SL and HL | 1 lessons, 4 questions |
| B2.1 | Programming fundamentals | SL and HL | 22 lessons, 62 questions |
| B2.2 | Data structures | SL and HL | 12 lessons, 46 questions |
| B2.3 | Programming constructs | SL and HL | 29 lessons, 70 questions |
| B2.4 | Programming algorithms | Mixed | 3 lessons, 14 questions |
| B2.5 | File processing | SL and HL | Coming |
| B3.1 | Fundamentals of OOP for a single class | SL and HL | 2 questions |
| B3.2 | Fundamentals of OOP for multiple classes | HL only | 1 questions |
| B4.1 | Fundamentals of ADTs | HL only | 2 questions |
How the course is assessed
As reported by several teacher and school-platform sources (the official guide is only on the IB's teacher site):
| Part | SL | HL |
|---|---|---|
| Paper 1: Theme A, with the case study in Section B | 1 h 15 min, about 35% | 2 h, about 40% |
| Paper 2: Theme B, programming in Java or Python | 1 h 15 min, about 35% | 2 h, about 40% |
| Internal assessment: a computational solution | 35 hours, 30% | 35 hours, 20% |
Sources disagree on a few details, such as the IA video length, so check with your teacher before you plan around an exact number.
What changed from the old course
- Paper 3 is gone. The pre-released case study now sits in Paper 1, Section B, and both SL and HL answer it.
- No more options. Databases, object-oriented programming and machine learning are part of the core for everyone.
- Machine learning is new. Topic A4 covers how models learn, preparing data, the main approaches (mostly HL) and the ethics.
- Real languages in Paper 2. Your school teaches Java or Python, and you program in that language in the exam and the IA.
- A new IA. The internal assessment is a computational solution with a word limit on the write-up (reported as 2,000 words) and a short video.
Key idea: Old past papers still help with programming, algorithms and networks, but nothing old covers machine learning or the new case study format.
How to use this map
Each topic in the table links to the lessons and questions that teach it. Where a topic says "coming", we have not written it yet. The programming topics (Theme B) are the furthest along, because Paper 2 is where practice with running code helps most.
Questions students ask
- Is machine learning in the IB Computer Science 2027 syllabus?
- Yes. Topic A4 is machine learning. The fundamentals and ethics are for everyone; data preprocessing and most of the approaches (such as neural networks) are reported as HL only.
- Is there still a Paper 3 in IB Computer Science?
- No. From May 2027 there are two papers. The case study that used to be Paper 3 is now Section B of Paper 1, for SL and HL.
- Can I use Python in IB Computer Science?
- Yes. The new course supports Java and Python. Your school picks one, and you use it for teaching, the IA and Paper 2.
- What is HL only in IB Computer Science 2027?
- Reported as HL only: translation (A1.4), alternative databases and data warehouses (A3.4), data preprocessing (A4.2), machine learning approaches (A4.3), OOP with multiple classes (B3.2) and abstract data types (B4.1), plus extra points inside some shared topics.