About the Reaction Time Test

What Is This Tool?

Our Reaction Time Test is a free browser tool that measures the elapsed time between a visual cue and your button activation. It uses the browser Performance API and requires no account, plugin, or installation.

How Accurate Is It?

The test uses performance.now(), a monotonic browser clock designed for elapsed-time measurement. Browsers may reduce exposed timer resolution for privacy and security. The final score also includes display, input-device, operating-system, event-dispatch, and browser effects, so it should not be treated as a direct measurement of neurological latency.

The Science of Reaction Time

Simple reaction time has been studied for more than a century, but results vary across laboratories and protocols. A calibrated 2015 study of 1,469 adults reported a mean simple visual reaction time of 231ms before hardware-delay correction and 213ms after correction. That study also demonstrates why an online score should always be interpreted together with the measurement method.

Types of Reaction Time Tests

Simple Reaction Time

In a simple reaction time test, there is one stimulus and one response. You see a signal and you respond. This is the type of test we offer, and it produces the fastest reaction times because no decision-making is required.

Choice Reaction Time

In a choice reaction time test, there are multiple possible stimuli and you must choose the correct response. For example, you might press different keys depending on which color appears. These tests are slower because they involve decision-making.

Auditory Reaction Time

Auditory reaction time tests use sound instead of a visual cue. Results from auditory and visual tasks should not be compared without matching the stimulus, response, hardware, timing method, and participant group.

Privacy and Data

Reaction-test scores and recent history are processed and stored locally in your browser; we do not send those scores to Google Analytics.

Test scores stay on this device. Google Analytics 4 separately measures standard site usage; it does not receive your reaction-time scores. Privacy Policy

Transparent methodology

Read how the timer, five-round median, consistency measure, local history, hardware limitations, sources, and correction process work on our Methodology page.