The term "cyclomatic complexity" sounds like it belongs in a computer science thesis, but the underlying idea is straightforward: it's a count of how many independent paths exist through a function's control flow. Every if, else if, loop, case and logical && or || adds another branch point, and another path the function could take.
Why the number correlates with bugs
Functions with more independent paths need more test cases to cover fully, and are harder for a reviewer to trace through mentally — which is why complexity scores correlate reasonably well with defect rates in practice, even though the metric itself is decades old and fairly crude by modern static-analysis standards.
What to actually do with the number
A complexity score under 10 is generally considered manageable. Above 20, most teams treat it as a strong signal that a function should be split into smaller pieces — not because the number itself is sacred, but because functions that score that high tend to genuinely be doing too many things at once.
TeckForge's Cyclomatic Complexity Estimator counts branch points in a pasted function and gives a rough score and rating — useful as a quick gut-check before a code review, not a replacement for a real static analysis tool wired into your CI pipeline.
