Fiducia TogetherAlgorithm
A set of steps for solving a problem. Not a program — a program is one way of writing an algorithm down.
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.
What it is
An algorithm is a finite sequence of unambiguous steps that solves a problem or performs a task. It can be written as pseudocode, as a flowchart, or in a programming language.
Where it applies
GCSE and A Level computer science, and it underlies everything else in the subject.
How it works
An algorithm must terminate, must be unambiguous at every step, and must work for all valid inputs. Efficiency matters: two algorithms can give the same answer and take wildly different amounts of time.
The standard GCSE algorithms are linear and binary search, and bubble, merge and insertion sort.
How to use it in your work
When asked to write one, use your board's pseudocode conventions or a flowchart — not a specific language unless the question says so.
Binary search requires a sorted list. Saying so is frequently a mark, and forgetting it is the classic error.
For efficiency comparisons, say why: binary search halves the search space each step, so it needs far fewer comparisons on a large list.
Where to get help
Your teacher and your board's specification — the pseudocode and the required language differ between boards. Bitesize covers the concepts; the computer science song runs the topics.
Revise this with a song
These are ours. We write revision songs because a lot of people remember a tune when they cannot remember a page, and because revising out loud in the kitchen beats staring at a highlighter.
- The Computer Science Song The GCSE computer science topics, set to music.
Where to read more
Last reviewed 2026-08-28 by Fiducia Together · Next review due 2027-08-28
Please note: This page explains a word or a process in education. It is general information about the system, the law and the guidance in England — not advice about your child, your school or your exam. If a decision is going against you, get advice from one of the free services we link to before you agree to anything or miss a deadline. If you are revising, check your own exam board's specification: boards word things differently and yours is the one that marks you.