A-Level Computer Science Topics Explained (AQA & OCR)

June 19, 2026

A-Level Computer Science covers a wide range of topics. This overview summarises the major areas in the AQA (7517) and OCR (H446) specifications so you can see the big picture and plan your revision.

Programming and computational thinking

Procedural and object-oriented programming, recursion, and the thinking skills (abstraction, decomposition, algorithmic thinking) that underpin the whole course.

Data structures

Arrays, records, lists, stacks, queues, linked lists, graphs, trees and hash tables — including how they work and when to use each.

Algorithms

Searching (linear, binary), sorting (bubble, merge, insertion), graph and tree traversals, and analysing efficiency with Big-O notation.

Theory of computation

Finite state machines, regular expressions, the Turing machine, and what it means for a problem to be computable.

Data representation

Binary, hexadecimal, two's complement, floating point, character sets, and how images and sound are stored.

Computer systems and architecture

The CPU, the fetch-decode-execute cycle, registers, assembly language, and the difference between hardware and software.

Networks and the internet

Network topologies, protocols, the TCP/IP stack, and the principles behind how the internet works.

Databases and SQL

Relational databases, normalisation, entity relationships, and writing SQL queries.

Security and ethics

Encryption, network security threats, and the legal, moral and ethical issues around computing.

Each of these areas is broad, so use a confidence checklist to prioritise. BrightRevision provides A-Level flashcards and quizzes across these topics so you can revise with active recall rather than just reading.