Code Speed Test — Benchmark Your Code

Run JavaScript benchmarks in your browser. Measure execution time, ops/sec, and compare algorithm performance — no install needed.

🖊️ Custom Code Runner

// JavaScript — write any synchronous code here
// The runner will execute it N times and measure ops/sec

function isPrime(n) {
  if (n < 2) return false;
  for (let i = 2; i <= Math.sqrt(n); i++) {
    if (n % i === 0) return false;
  }
  return true;
}

// Find all primes up to 10,000
const primes = [];
for (let i = 2; i <= 10000; i++) {
  if (isPrime(i)) primes.push(i);
}
return primes.length; // return a value to prevent dead-code elimination

Iterations:

🏁 Preset Benchmarks

Click any card to load it into the runner above.

🧠 What This Measures

Execution time per iteration of your JavaScript code, run in your browser's JS engine (V8, SpiderMonkey, JavaScriptCore). Results reflect your CPU clock speed, JS engine JIT optimization, and memory bandwidth.

⚠️ Benchmark Tips

Close other tabs for consistent results
Run at least 50 iterations for stable numbers
Use return to prevent dead-code elimination
Avoid async code — the runner is synchronous
Warm-up is included automatically (first 3 runs discarded)

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Memory Speed — RAM bandwidth
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