Last updated 28 August 2026
The magic number seven
In 1956 the psychologist George Miller published a paper arguing that short-term memory holds about seven items, give or take two, and the figure has stuck in popular usage ever since. Later work suggests the true number for unrelated items is smaller — closer to four — and that anything above it comes from chunking rather than raw capacity. That is what you are really testing here. Most people stall somewhere between seven and nine digits. Getting past that almost always means you have stopped storing digits and started storing groups of them, the way phone numbers are written in blocks rather than as one long string.
Common questions
What is a normal digit span?
Most adults manage seven to nine digits. Reaching double figures usually means you are chunking — grouping digits into pairs or triples and remembering those as single units rather than storing each digit separately.
Why does the sequence stay on screen longer at higher levels?
The display time scales with length, roughly a second per digit. Keeping it fixed would make the test measure reading speed as much as memory, which is not the point.
Are the numbers random?
Yes, generated fresh each level. The first digit is never zero, so the sequence reads as a number rather than something with a leading zero that is easy to lose track of.
Is my score saved?
Your best level is stored in your own browser only. Nothing is uploaded and there is no account.