How to use this test
Read the number
A one-digit number starts the run. Viewing time is 1.2 seconds plus 0.6 seconds per digit, so longer numbers get longer exposure.
Recall after it disappears
Type all digits in their original order and submit. There is no typing deadline; spaces are ignored.
Continue or review
A correct answer unlocks the next round. A wrong answer shows your entry and the expected number. Your score is the longest length recalled correctly.
What we check
Every round generates a fresh number with no leading zero. Digits are stored as text, not a numeric value, so long answers retain every digit exactly.
This is a forward-recall game with increasing exposure time. It is not a standardized digit-span procedure. The run ends on an incorrect answer or after 20 correct digits.
What this test can’t tell you
This is a practice game, not an IQ test, health screening or clinical assessment. The score describes this run, not your overall ability. There are no population rankings.
Something not working?
My phone hides the number with its keyboard
The answer field stays hidden during memorization. It appears only when the number has disappeared.
My answer is rejected
Use digits 0–9. Spaces are accepted, but punctuation and letters are not. Invalid formatting does not end your run.
Common questions
Can I group the digits?
Yes. Grouping is a reasonable memory strategy. Keep your strategy consistent when comparing your own results, and avoid writing the number down if you want a recall challenge.
Why does the display time increase?
Longer strings take longer to read. The exposure rule is shown here so you can understand the result rather than compare it with a test that uses different timing.
Does a high score measure intelligence?
No. Familiarity, strategy and the rules of this particular task can affect the score. It is not an intelligence measure.