Benchmark Builder

Snippet A

for (let i = 0; i < 100000; i++) { Math.sqrt(i); }

Snippet B

for (let i = 0; i < 100000; i++) { i ** 0.5; }

Iterations

Snippet A — Avg Time

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Snippet B — Avg Time

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Faster

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Snippets run only in your own browser tab — nothing is sent anywhere. Only run code you trust.

How to use this benchmark builder

Write or paste two JavaScript snippets to compare.
Set how many iterations to average over.
Click "Run Benchmark" to see which one is faster in your browser.

Why do results vary between runs?

JavaScript engines use just-in-time compilation and various optimizations that can make timing slightly inconsistent between runs — averaging over more iterations gives a more reliable comparison.

Is this a reliable way to benchmark code?

It's a useful rough comparison for quick decisions, but for rigorous benchmarking, dedicated tools that account for JIT warm-up and garbage collection are more accurate.

Is it safe to paste code I found online?

Only run code you trust and understand — it executes directly in your browser tab with the same permissions as this page, though nothing leaves your device.