What does this tool do?
Reaction Time Test is a reflex test that measures your visual reaction speed in milliseconds by asking you to click the moment the box turns green. As you take multiple attempts, it calculates your best and average time. All timing is done in the browser with a high-resolution clock.
How to use it
- Enter your values into the fields.
- The result is calculated instantly.
- Read or copy the result.
How it works
When the test starts the box stays red and, after a random wait, turns green; at that instant a timestamp is recorded with performance.now(). When you click, the difference between the two timestamps is your reaction time in milliseconds. If you click before green, it's flagged as an early start and that attempt doesn't count.
Common use cases
Use it to warm up and track gamers' reflexes, compete with friends for the fastest reaction, or observe how sleep and caffeine affect alertness. The average human visual reaction time is usually in the 200-300 ms range, so you can judge your own results against that reference.
Frequently asked questions
What should a typical reaction time be in ms?
Most people react to visual stimuli between 200-300 ms. Below 200 ms is considered very fast; results can vary with screen latency, your mouse, and the time of day.
What happens if I click before it turns green?
An early click is detected and the attempt is voided, so you can't get a low time by guessing. The box resets and you're asked to wait again.
Is Reaction Time Test free?
Yes. Reaction Time Test and all 300+ tools on MagmaNex are completely free with no signup or account required.
Is my data safe?
Yes. Everything runs locally in your browser. The data you enter is never sent to a server, stored, or shared.
Does it work on mobile?
Yes. Reaction Time Test works on phones, tablets and desktops — no app download needed.
🔒 Privacy: everything runs in your browser, your data is never sent to a server.