The number memory test checks your digit span: a number flashes on screen, then you type it back from memory. Each correct answer adds another digit, so the number keeps growing until you slip.
How many digits can you remember? →
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A number flashes on screen, you hold it in your head, then type it back. Get it right and the number grows; the run ends when your memory finally taps out. This is a classic digit span test — one of the oldest and most-studied measures of short-term memory — and your score is the longest number you recalled correctly.
The test starts at a comfortable three digits and only lengthens the span once you've proven a length, so one lucky recall never rockets you somewhere you can't survive. Each number stays on screen roughly a second per digit — long enough to read, short enough that you have to actually remember.
Typing the digits back in order tests pure short-term storage. Switch to reverse mode and you must type them backwards — a much heavier lift, because now you're storing and manipulating, which is working memory proper. Expect your reverse span to run a couple of digits shorter; that's normal for everyone.
Don't memorise nine digits — memorise three chunks of three. Chunking is how memory athletes do it: group digits like a phone number, give them a rhythm, or attach meaning (a year, a price). Most adults naturally hold around seven digits — the famous "seven, plus or minus two" — but chunking is the lever that pushes past it. More in our guide to how many digits you can remember.
About seven digits forward for most adults, and around five in reverse. Details in the number memory span guide.
Roughly one second per digit, with a speed setting if you want it kinder or crueller.
That's the natural capacity of un-chunked short-term memory. Grouping digits into twos and threes is how you break through.