Digit span · Memory
Number Span Test
A number loads into the register one digit at a time. Hold it, then key it back.
No IQ score. No cognitive age. No percentile we can’t source.
Digit span · Memory
Number Span
A number loads into the register one digit at a time. Hold it, then key it back. Read it as a calm instrument, or stack the register as high as it will go.
Your span is the longest number you reproduce. Forward is short-term storage; keying it back in reverse loads working memory — usually a digit or two shorter.
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What this measures
This measures your digit span — how long a sequence of digits you can hold and reproduce. Forward span is a short-term memory span; keying the number back in reverse loads working memory. Digit span is one of the subtests inside the batteries that produce a general-ability score; nothing here is such a score, and nothing is shown as one; and because most people chunk the digits, the number is higher than the roughly four items short-term memory holds as raw capacity (Cowan).
Read it two ways: Gauge takes two calm passes, forward then back, for your real span as a band; Stack is the adaptive game — lock a length and the number grows, no game-over. Forward is short-term storage; reverse loads working memory.
How to hold a longer number
You mostly get better at this task — grouping the digits into chunks, keeping a steady inner voice, and not letting a long one rattle you. That is a real, honest thing to practise, and it is why the longest span you reproduce is the number that matters. It makes you better at holding a number in mind on this screen.
Questions
- What is a good number span?
- We do not publish one: there is no norming sample behind any number here, so a good span would be a figure we invented. Your forward and backward spans are shown side by side, and your own best on this device is the thing to beat. Expect the number to move with attention, tiredness and practice — yours, not a verdict on you.
- What is the difference between Forward and Backward?
- Forward asks you to key the digits back in the order they appeared — that is a short-term memory span. Backward asks you to key them back in reverse, which means holding the number and manipulating it at the same time — a working-memory task, and usually a digit or two shorter.
- What is the difference between Gauge and Stack?
- Gauge is the honest instrument: two sequences at each length, which is how the standard digit-span procedure runs, starting at three digits and stopping a direction when you miss both at a length. It runs forward then backward on its own and reports each span as a band. Stack is the game: an adaptive ladder where two clean answers at a length lock it and the number grows by one, a single miss steps you softly down, and two misses in a row — or banking when you like — ends the run. There is no game-over.
- How is my score calculated?
- In Gauge, your span is the longest length you reproduce, with half credit for getting one of two at the next length up (so a span can read 6.5); it is reported forward and backward, side by side, with the total you got right. In Stack, your score is your peak span — the longest number you keyed back exactly this run — with the length you settled around shown beside it. Either way the number is the longest number you can hold, nothing more.
- Why is there a blank flash between digits, and does the game speed up?
- The blank makes a repeated digit read as two separate flashes rather than one. Each digit appears for the same short moment with a blank gap after it, and that rate never changes — not between digits, not as the numbers get longer, not from one run to the next. Stack makes the number longer, never faster: what you are measuring is how much you can hold, not how fast the screen moves.
- Can I train my span?
- You will get better at this task — chunking the digits, keeping a steady inner voice, not panicking on a long one. That is real and worth practising. It makes you better at holding numbers here.