Reaction Time Test
Click the moment it turns green. Measured over five rounds.
Reading your result
Fill in every field and the steps will be spelled out here.
How it is calculated
Human visual reaction time usually falls between 200 and 250 ms. That covers light reaching the eye, the brain deciding, and the finger moving — and much of it is nerve conduction, which practice barely shortens. Anything under 100 ms means the click anticipated the change rather than responded to it.
Your display and input device are measured along with you. A 60 Hz monitor refreshes only every 16 ms, and wireless mice and touchscreens add their own delay on top. The same person can score 30–50 ms apart on different hardware, so tracking your own results on one device says far more than comparing against someone else.
That is why the wait is randomised. A fixed delay lets you learn the rhythm and click ahead of it, which measures prediction rather than reaction. This test waits between 1.2 and 5 seconds, and clicking before the change voids that round.
Condition matters more than people expect. Sleep debt and fatigue slow you down; caffeine speeds you up slightly and temporarily. Results drift over the course of a day, so several runs describe your state better than a single number.
Frequently asked questions
What is a normal reaction time?
Simple visual reaction is typically 200–250 ms. Under 200 ms is quick, over 300 ms is on the relaxed side. It tends to lengthen gradually with age.
I got under 100 ms — is that real?
Almost certainly not. Nerve conduction and muscle response impose a floor that makes genuine visual reaction below that range implausible. Scores that low usually mean the click was timed in advance.
Does my hardware affect the result?
Yes. Refresh rate, input latency and browser state all fold into the number. A 60 Hz display alone adds about 8 ms on average. Comparing scores across devices tells you little.
Where is my best score kept?
In this browser only. Nothing is sent to a server, so it will not appear on your other devices and clearing browser data removes it.
Related calculators
This is for fun. The measurement includes display and input latency and cannot support any medical or occupational judgement. If you are concerned about your reaction time, speak to a doctor.