Reaction Time Test

What Is Reaction Time?

Reaction time (RT) is the delay between the appearance of a stimulus and the initiation of a response. In large public datasets, the median visual RT is ≈ 273 ms, with an average around 284 ms.

How This Test Works

The screen turns green at a random interval (1–5 s). Your browser records the exact time it changes colour and the exact moment you click, then subtracts the two to produce your RT in milliseconds. Note that display latency and input lag add a few extra ms to any online measurement.

Typical Human Benchmarks

• Everyday adults: 250–300 ms for visual cues.
• Trained esports players: often 150–200 ms with high-Hz monitors.
• Children & seniors: RT increases steadily after ~24 years old and again after ~60.

Factors That Influence RT

• Age: RT slows ~2 ms per decade after age 20.
• Fitness: Regular exercise improves RT by ~10-15 ms.
• Fatigue: Sleep deprivation adds ~20-30 ms.
• Distraction: Multitasking increases RT by ~50-100 ms.
• Complexity: More complex decisions take longer.
• Practice: Training can improve RT by 10-20%.

Can You Train Reaction Time?

Yes. Simple drills such as ball-drop catches, sprints with unpredictable start cues, or cognitive games can yield measurable gains in 4–6 weeks. Consistent sleep, hydration, and minimizing multitasking also help.

Simple vs. Choice Reaction Time

Reaction time tasks come in two main forms. In a simple reaction time (SRT) task, a single stimulus maps to a single response: the screen turns green and you click as fast as you can. In a choice reaction time (CRT) task, several stimuli map to different responses, so you must identify the stimulus before deciding what to do. The gap between SRT and CRT is called decision time — the extra milliseconds spent on perceiving and choosing, rather than just responding. Hick's Law describes how this decision time grows as the number of possible choices increases.

Most online tests, including this one, measure simple reaction time. To explore the choice version and compare the two, try the Deary-Liewald task or the choice reaction time experiment elsewhere on this site.

Reaction Time in Cognitive Psychology

Reaction time is one of the oldest and most widely used dependent variables in experimental psychology. As early as 1868, Dutch physiologist Franciscus Donders showed that subtracting simple from choice reaction time lets researchers estimate the duration of a single mental operation, such as discriminating between two stimuli — the foundation of mental chronometry.

Modern research still builds on this idea. Faster, more consistent reaction times correlate modestly with higher general intelligence, and tasks such as the Deary-Liewald protocol are used in clinical and differential psychology to measure processing speed. Your median reaction time here is a rough sample of the same underlying cognitive speed researchers study in the lab.

How Reaction Time Is Measured in Research

In laboratory settings, reaction time is recorded to the millisecond using dedicated hardware or tightly controlled software, with display latency and input lag accounted for. Online tests like this one rely on browser timers, so absolute values run a few milliseconds slower than lab equipment — still useful for tracking your own improvement, less meaningful as an absolute score.

Researchers rarely trust a single trial. Reaction time distributions are skewed: occasional slow responses (distraction, a blink, a mistimed click) inflate the average. That is why serious studies report the median rather than the mean, and why you should judge your performance by your median across several rounds rather than by your single fastest click.

What Is a Good Reaction Time, by Context

There is no one 'good' number, because expectations depend on context. For everyday adults, a median around 250-300 ms is typical, while trained esports players often reach 150-200 ms on high-refresh displays. In cognitive research, the focus is rarely on how fast you are in absolute terms — it is on how consistent your responses are and how they change with practice, fatigue, or age.

If your median here is below roughly 150 ms, you may be anticipating the green flash rather than reacting to it — the test flags premature clicks for exactly this reason. If it is above 300 ms, screen latency, device type, or fatigue are more likely explanations than your 'true' processing speed. Compare like with like: same screen, same browser, rested.

A Simple 4-6 Week Training Approach

Reaction speed is trainable, but training works best when it is short, frequent, and specific. A practical approach: do 2-3 short sessions per week, with 10-20 trials each, spread across different days rather than one long session. Track your median per session instead of your best single click — the median is what actually improves with practice.

Real-world transfer matters more than chasing numbers on one screen. Ball-drop catches, unpredictable start signals in sprints or sports, and fast-paced reaction games all train the same perception-to-action loop. Sleep is the hidden variable: sleep deprivation reliably adds 20-30 ms, roughly cancelling several weeks of training gains.

Average RT by Age (Quick Reference)