Yes. You can use it at no charge.

Is it accurate on mobile?

Touch and device latency can shift results—compare on the same device for consistency.

Can training improve reaction time?

Practice and healthy habits help some people; results vary widely.

Focus, fatigue, and environment change—and the browser adds delay.

Try 5–10 attempts and look at an average or typical range.

This is a simple reaction test: click as soon as the screen changes color.

Your time is shown in milliseconds (ms).

Wait for green on red—click too early and you fail. Free in your browser.

Click when it turns green

Click (or tap) as fast as you can when the panel turns green. It starts red while you wait.

Reaction time is the delay between noticing a stimulus and completing a response—see the color change, decide, then click.

Roughly stimulus → processing → movement. Sleep, fatigue, focus, and device lag all matter.

Informal ranges for simple visual reaction tests; not a clinical norm.

Many casual sources cite ~200ms as a rough ballpark for simple visual tasks. This page is not medical testing.

One number reflects that moment—focus, tiredness, and environment all shift results.

Lower ms usually means faster click-to-green, but prefer trends over many tries than a single score.

Browser, display, and input latency add noise.

Everyone differs; habits help some people more than others.

It matters in life beyond games—but this page is only a casual screen test.

Quick setup — One click to start; your result appears within seconds.
Millisecond readout — Results are shown to the nearest millisecond, so even small differences are visible.
Easy to repeat — Run several trials and average them for a more reliable number.
Results vary with focus and fatigue — Use it as a lightweight self-check when you want to gauge your current alertness.

Q. Is it free?: Yes. You can use it at no charge.
Q. Is it accurate on mobile?: Touch and device latency can shift results—compare on the same device for consistency.
Q. Can training improve reaction time?: Practice and healthy habits help some people; results vary widely.
Q. Why do scores differ each time?: Focus, fatigue, and environment change—and the browser adds delay.
Q. How many runs should I take?: Try 5–10 attempts and look at an average or typical range.

⚡ Wait for green, click fast—repeat runs to track your trend.