How to take the reaction time test
Use a mouse, touch or keyboard, whichever you like, but stick to one method when comparing results.
- Click the blue screen (or press Space/Enter). It turns red.
- After a random 1.5–5 second wait it turns green. Click as fast as you can.
- Clicking before green counts as a false start and the round restarts without a time.
- After the chosen number of rounds (5 by default) you get your average, fastest time and spread, saved in this browser.
- Save a result image or share a challenge link with friends.
What is a good reaction time?
Human Benchmark, a well-known online reaction test, reports a median of 273 ms and an average of 284 ms from more than 81 million recorded clicks. Your result is compared with that median.
Lab measurements are faster. Summaries of reaction time research put mean simple reaction time for college-age adults at about 180–200 ms for visual stimuli and about 140–160 ms for sounds. The gap is mostly device latency, explained below.
The labels (Very fast to Slow) are this site’s own 50 ms bands starting at 200 ms, loosely centred on that median. They are for fun, not an official scale.
Why your result includes device lag
Human Benchmark notes that a computer can add 10–50 ms on top of human reaction time, and some TVs add as much as 150 ms.
- Refresh rate: one frame lasts about 16.7 ms at 60 Hz and about 6.9 ms at 144 Hz.
- Display processing: TVs add more lag; turn on game mode.
- Input devices: mice, keyboards and touchscreens all take time to report input, and it varies by device.
- System load: heavy background work can delay screen updates.
How this test measures time
The wait time comes from the browser’s cryptographic random number generator, so it cannot be predicted. Timing starts at the next frame after the screen turns green, which is when it is actually drawn, and stops at the moment you press down (not release), using the input event’s high-resolution timestamp.
Input that arrives before green is drawn counts as a false start. If you switch tabs mid-round, the round pauses and continues when you click again.
Reaction time and age
Research summaries describe simple reaction time getting faster from childhood into the late 20s, slowing gradually through the 50s and 60s, and slowing faster from the 70s. Tracking your own results on the same device is more meaningful than comparing with others.
FAQ
What is the average reaction time?
Human Benchmark publishes a median of 273 ms and an average of 284 ms. Lab studies put mean simple visual reaction time around 180–200 ms; online tests are slower because of monitor and input latency.
Why is my phone slower than my PC?
Touchscreens and displays take different amounts of time to register and show changes on each device. Compare phone results with phone results and PC results with PC results.
I keep getting "Too soon!".
Any input before green is drawn is a false start. The wait is random between 1.5 and 5 seconds every time, so react to the colour change instead of guessing.
Should I click or press Space?
Whichever you prefer, but use the same method when comparing results, since input devices differ in latency.
Where is my history saved?
Your last 50 sets are stored only in this browser (localStorage) and never uploaded. Use Clear history to delete them.