Code Complexity Analyzer

Code complexity analysis measures how complicated your source code is using software metrics. The most common metric is cyclomatic complexity, developed by Thomas McCabe in 1976, which counts the number of linearly independent paths through a program's source code. Each decision point (if, else, switch case, loop, catch, ternary operator, logical operator) increases the complexity score.

This tool also calculates cognitive complexity (how hard code is to understand for humans), nesting depth (maximum level of nested control structures), and maintainability index (a composite score from 0-100 combining cyclomatic complexity, lines of code, and Halstead volume). Lower complexity scores indicate code that is easier to test, debug, and maintain. Industry best practices recommend keeping cyclomatic complexity under 10 per function and nesting depth under 4 levels.

1. Paste code — Paste your source code into the text area. Supports JavaScript, TypeScript, Python, PHP, Java, Go, Ruby, C++, and C#.
2. Click Analyze — Press the Analyze button to instantly compute cyclomatic complexity, cognitive complexity, nesting depth, and maintainability index for each function.
3. Review results — The overview shows aggregate metrics and an overall maintainability score (0-100). The functions table breaks down complexity per function with color-coded assessments.
4. Try examples — Use Simple Example to see well-structured code with low complexity, or Complex Example to see how deeply nested code with many decision paths produces high scores.