Reaction Time Test
Click as soon as the screen turns green and see how fast your reflexes are.
Average human reaction time is around 200–250 ms. Clicking before the screen turns green counts as a false start.
Wait for the colour to change, then click or tap as fast as you can. The test runs several rounds and reports your best, worst and average time in milliseconds, along with how that compares to typical results.
Most people land between 200 and 300 milliseconds for a simple visual reaction. That figure is not a measure of intelligence or skill — it's largely a measure of how long signals take to travel through your nervous system, plus how well you slept.
Where the milliseconds actually go
| Stage | Approximate time |
|---|---|
| Light reaches the retina, converted to a neural signal | 20–40 ms |
| Signal travels to the visual cortex | 20–30 ms |
| The brain recognises the change and decides to act | 50–100 ms |
| Motor command travels to the hand | 20–30 ms |
| Muscle contracts, finger moves, switch registers | 30–50 ms |
| Display and input hardware latency | 10–50 ms |
A meaningful share of your measured time is hardware, not you. A 60 Hz screen adds up to 16 ms of display latency alone, and a wireless mouse or touchscreen adds more.
What affects your score
- Age. Reaction time peaks in the early twenties and slows gradually afterwards, by roughly 10 ms per decade.
- Sleep. A single night of poor sleep can add 50 ms or more, making this one of the more sensitive everyday fatigue indicators.
- Caffeine improves reaction time modestly and reliably — typically 10–20 ms.
- Anticipation. If you can predict the timing, you're measuring prediction rather than reaction, which is why the delay here is randomised.
- Auditory reactions are faster than visual ones, around 150 ms, because sound is processed with fewer stages.
- Hardware: a 144 Hz monitor and a wired mouse can shave 20–30 ms off an identical biological response.
Simple versus choice reaction
This is a simple reaction test: one stimulus, one response, nothing to decide. Choice reaction — where you must pick between responses depending on what appeared — is substantially slower, and the gap grows with the number of options. That relationship is regular enough to be formalised as Hick's law: reaction time rises roughly with the logarithm of the number of choices.
It's a genuinely useful idea outside the laboratory. Interface designers use it to argue for fewer, clearer options at any decision point, because each additional choice costs the user measurable time — and this test is the baseline those measurements are compared against.
Frequently asked questions
- What is a good reaction time?
- Most people fall between 200 and 300 ms on a simple visual test, with around 250 ms typical. Under 200 ms is genuinely fast; under 150 ms usually means you anticipated rather than reacted.
- Why is my score worse than I expected?
- Screen refresh rate, input device latency, tiredness and the browser itself all add milliseconds. A 60 Hz display alone can contribute up to 16 ms before your nervous system is involved.
- Can I improve my reaction time?
- Somewhat. Sleep, caffeine and practice all help at the margins, and task-specific training helps more. The underlying nerve conduction speed is largely fixed, so gains are measured in tens of milliseconds, not hundreds.
- Why is the delay before the colour change random?
- So you can't anticipate it. With a fixed delay you'd be measuring your sense of timing rather than your reaction, and scores would drop below what's biologically possible.
- Do gamers really have faster reactions?
- Action game players do measurably better on visual reaction and attention tasks in controlled studies, though how much is training and how much is self-selection remains debated.
- Is auditory reaction faster than visual?
- Yes, typically around 150 ms compared with 250 ms. Sound takes a shorter neural path with fewer processing stages, which is why sprint races start with a gun rather than a light.