Big O Complexity Analyzer
Runs locally in your browserEstimate time and space complexity of JavaScript, TypeScript and Python with confidence levels
Source Code
Limit: 200 KiB, 10,000 lines. Code is never executed. 0 bytes · 0 lines
Complexity Report
Results appear here after you analyze code.
Paste code or load an example, then select Analyze complexity.
Analysis runs locally in a browser worker. Source code is not uploaded, executed or sent to AI services. The draft and language may be kept in this browser until you reset.
Big O Complexity Analyzer
Estimate time and space complexity of JavaScript, TypeScript and Python code with syntax-tree static analysis, confidence levels and line-by-line explanations.
How to use
Choose a language, paste a function or script and select Analyze complexity. Pick a function from the scope list, select a finding to highlight its lines, compare growth curves, then copy the report or download Markdown or JSON.
How the analysis works
The code is parsed into a syntax tree, never executed. Loop bounds, multiplicative steps, nested loops, recursion shapes and known library operations are combined symbolically; the dominant term becomes the estimate. Each estimate lists what n means.
Limits and confidence
Results are estimates, not proofs. Dynamic dispatch, unknown library calls, input-dependent recursion, amortized behavior, concurrency, I/O and reflection lower confidence. Limits: 200 KiB, 10,000 lines, 50,000 syntax nodes, nesting depth 200 and a 5-second analysis budget.
Privacy
Analysis runs locally in a browser worker. Source code is not uploaded, executed or sent to AI services. The draft and language may be kept in this browser until you reset.
