CPU benchmark
Press Start and wait a few seconds. The page times four fixed tasks in a Web Worker so the page stays responsive, then shows a score. The score means something only next to your own other runs on this page.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Close heavy tabs and, on a laptop, plug in the charger.
- Press Start and wait for the score.
- Run it a few times; the page lists the scores and the change against the previous run.
How it works
A Web Worker runs four fixed tasks one after another and times each with performance.now. The total of the four times gives the score: 100 000 / total ms. Stop or leaving the page ends the worker.
Worked example
Times of 300 + 250 + 200 + 250 ms total 1000 ms, so the score is 100 000 / 1000 = 100. A later run of 800 ms scores 125, which is +25 % against the first.
Tips
- Compare the same browser on the same device in the same power mode.
- A drop on the third run on a phone is often heat throttling.
Frequently asked questions
What does the score mean?
It is 100 000 divided by the total time in milliseconds. A run that takes 1000 ms scores 100, and halving the time doubles the score. The number only has meaning compared with your own runs on this page.
Can I compare my score with other people's?
Not reliably. Browser versions, operating systems, power settings and background load all change the result, so this page does not rank devices and makes no claim about how a given chip performs.
Why do my scores vary between runs?
Modern CPUs change speed with temperature and power mode, and the browser may schedule the worker differently. Run it three times and look at the best and the typical value.
What work does it do?
Counting primes with a sieve, recursive Fibonacci, sorting pseudo-random numbers and a floating-point loop. All are fixed, so each run does the same work, and all run on one thread in a Web Worker.