IGCSE vs IB vs A-Level Computer Science: What Parents Should Know

Families at international schools often meet more than one computer science qualification: IGCSE at 14 to 16, then IB Diploma or A-Level at 16 to 18. They share a core but test it differently, and knowing the differences helps you support your child.

IGCSE Computer Science

IGCSE (Cambridge or Edexcel) is the first formal computer science qualification for most international students. It covers how computers work (data representation, hardware, networks and security) alongside algorithms and programming. Pseudocode and trace tables appear heavily in the exams, so students need to read and write algorithms on paper, not just in an editor.

The most common difficulty is the programming and algorithms paper. Students who only practise on a computer struggle when they have to write correct logic by hand under time pressure.

A-Level Computer Science

A-Level (Cambridge International, AQA or OCR) goes much deeper: more advanced data structures, object-oriented programming, theory of computation, and more mathematical content. Boards differ in assessment. AQA and OCR include a substantial programming project (the non-exam assessment, or NEA), while Cambridge International assesses programming through exam papers, including a practical paper.

For A-Level, the biggest jump from IGCSE is the independence required: designing larger programs, not just completing short exercises.

IB Diploma Computer Science

IB Computer Science is offered at Standard and Higher Level, and includes an Internal Assessment in which students develop a computational solution and document it. The IB updated the course for first teaching in 2025, so check which version your child's school follows.

The IA rewards planning and documentation as much as code. Students who leave it late or skip the design stage lose marks that are easy to keep.

What they have in common

• Logical problem solving and algorithms.
• Programming, very often in Python.
• Theory that has to be explained precisely in exam language.

How to support your child

Find out the exact board and specification code, because Cambridge, Edexcel, AQA, OCR and IB papers differ in style. Encourage regular hand-written algorithm practice, and get coursework started early with a clear plan. A tutor who knows the specific board can help most with exam technique and project planning, while the student does the work themselves.