Cyclomatic Complexity
Cyclomatic complexity is a software metric that measures the number of independent execution paths through a program.
“The maximum number of linear, independent paths through a program.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Cyclomatic Complexity?
The metric is calculated from the program's control flow and helps estimate testing effort and code complexity.
Complexity measurement: More decision points generally increase cyclomatic complexity.
Testing relevance: Higher complexity often requires more structural test cases.
Maintainability: Simpler code is usually easier to understand and maintain.
Real World Example
A regulated product team is preparing a release where Cyclomatic complexity appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Cyclomatic complexity as interchangeable with nearby ISTQB terms. That makes test scope blurry and can lead to weak evidence for the release decision.
The tester anchors the discussion in the official definition, asks where the concept appears in the product, and designs examples that show the difference between Cyclomatic complexity and similar ideas.
The page becomes useful in practice because Cyclomatic complexity is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which statement BEST describes Cyclomatic complexity in the context of ISTQB terminology?
Question 2
A tester needs to explain Cyclomatic complexity to a non‑technical stakeholder. Which approach is MOST appropriate?
Test your knowledge with real ISTQB-style questions
You’ve learned Cyclomatic Complexity. Test your understanding with topic-specific questions in our Mock Exams.