Guides
The tests give you a number. These explain what the number is made of, what moves it, and which claims about it are worth believing.
- How accurate is a browser reaction time test?Where the extra 80 ms comes from, and what we measured building this.
- How to improve your reaction timeWhat works — sleep, timing, warm-up, hardware — and what does not.
- Do brain training games actually work?Near transfer, far transfer, and why this site measures instead of trains.
Why these exist
A test result on its own invites the wrong conclusion. Two hundred and eighty milliseconds sounds slow next to a published average of 231, until you know that a browser adds roughly 80 ms nobody spent, that a 60 Hz screen costs about 8 ms more than a 144 Hz one, and that your own trials scatter by around 40 ms regardless. The guides carry the context that makes a number honest, including the parts that make our own numbers look less impressive.
Everything factual here is either linked to its source or was measured by us while building the tests, and where we measured it ourselves the page says so. If something is wrong, write to ysc9550@gmail.com and it gets corrected. Ready to get a number first? Start with the reaction time test or the full benchmark.
How to use these alongside the tests
Take a measurement first, then read. A number in front of you makes the context concrete: once you have seen your own median and the spread of your five rounds, the claim that within-person variability runs around 40 milliseconds stops being a statistic and starts explaining the run you just did. Start with the reaction time test, which takes about thirty seconds, or the full benchmark if you want all six.
Then read the measurement guide before you compare yourself with anyone. It is the one that changes how you read every other number on the site, because it explains why the figure on your screen is not the figure in your nervous system, and why a laptop result and a desktop result are two different measurements rather than two attempts at the same one.
The practice guide is worth reading before you decide you are slow. Most of what separates a disappointing run from a good one is sleep, time of day, warm-up and equipment rather than anything permanent about you, and those are all things you control. The evidence guide is the sceptical one: it explains why we call this site a measurement tool and not training, and what the research actually supports when someone tells you a game will make you sharper.
What we will not do here
We will not publish a number without saying where it came from. Every figure in these guides is either linked to a peer-reviewed source or was measured by us while building the tests, and the ones we measured ourselves are labelled as ours rather than dressed up as research. Where no published norm fits one of our tests, the test shows no percentile at all rather than an invented one — four of the six are in that position, and the methodology page names them.
We also will not tell you that repeating these tests will improve your cognition, because the evidence does not support it. What repetition reliably does is make you better at these particular tests, which is useful to know when you look at your own history and see a steep early improvement.