Reaction time test
Ready when you are
Read the instructions, then press Start test. Wait for the signal, then respond as fast as you can.
Wait for the signal
Responding before the signal arrives counts as too early. The delay is random, between one and three seconds.
Now
Respond as fast as you can.
Your reaction time
—ms
—Elapsed time measured with the browser's high-resolution timer.
Too early
The signal had not arrived yet, so this attempt was not recorded.
Missed
The response window closed before your input arrived, so this attempt was not recorded.
Catch the ruler as soon as it starts to fall. Your time is measured by the browser's high-resolution timer, not by how far the ruler travelled.
Amber flashes are fakes — flinch and the attempt is over. React only to the sustained green board. Your result shows how many fakes you dodged.
Set your seconds on the slider, then go full throttle while the timer runs down. Every tap, click, or Space press counts — keyboard mashers welcome. Your score is your average milliseconds per tap.
0
taps
5.0s
Trial 1 of 5
Five colour changes in a row. Your score is the mean of all five.
Run voided — too many early or missed trials, so no score was recorded. Start again when you are ready.
Waiting for the signal…
Best this test
—ms
Rank
Unranked
play to rank up
Day streak
0days
Tests today
0/ 5 goal
Next rank: —
react faster to climb
Copied — paste it anywhere to challenge a friend.
Tip: press Space anywhere on the test to start & react. Every attempt saves to your history below.
Calibration
All three controls are off by default and each one works on its own. Turning one on never changes what the other two do, because each reads one value and adjusts one stage of an attempt. Switching a control off drops its adjustment and keeps the value you entered.
Result stage
Latency compensation
Applies to all five modes.
Measures how long your input pipeline takes to deliver an event, then subtracts that from your result so the number reflects your reflexes rather than your hardware. Five rounds, and the median of the accepted ones is used.
Device latency:0 ms
The measurement did not complete — too few rounds landed in the plausible range. Device latency stays at 0 ms. Try again without moving the pointer.
Rendering stage
Screen scale
Applies to Ruler Drop only.
Draws the on-screen ruler's markings at true physical scale for your display, so a centimetre on the ruler is a centimetre. Affects the markings only — it never changes your reaction time.
Enter a screen diagonal between 5 and 60 inches. The markings keep the scale they were last drawn at.
This control applies to Ruler Drop only — it is the only mode that draws a ruler. Switch to Ruler Drop to use it.
Trigger stage
Ready gate
Applies to all five modes.
Holds the signal until you say you are ready, instead of starting the random delay the moment you activate the surface. Keeps anticipation and distraction out of the reading. Affects when the signal starts and nothing else.
History
Ruler Drop— every mode keeps its own results, so nothing is averaged across modes.
This browser is not allowing local storage, so results are kept only until you close the page. Everything else works as normal.
Latest
—ms
Best
—ms
Mean
—ms
Attempts
0
Last 20 attempts
faster is higher
No attempts recorded for this mode yet. Run it once and your times show up here.