A number flashes, you type it back, and each round adds one digit. See your digit span and how your past runs are spread. Runs on your device.
A number memory test measures your digit span, which is the longest string of digits you can see once and type back correctly. On this page, level 1 shows 1 digit, level 2 shows 2 digits, and each correct answer adds one more digit. The first mistake ends the run, and the game stops at 40 digits (a correct level-40 answer ends it as "maximum completed"). If you type level 6 correctly and miss level 7, your digit span is 6. If you miss level 1, your span is 0. Each number is random and never starts with 0, so a level always has exactly that many digits. The number stays on screen for 1 second plus half a second per digit: 1.5 seconds at level 1, 4.5 seconds at level 7 and 11 seconds at level 20.
George Miller's 1956 paper, The Magical Number Seven, Plus or Minus Two, in Psychological Review, discussed roughly seven items, digits among them, in immediate memory, as a rough estimate rather than a norm. Later work argued that the true limit is smaller when people cannot group items: Nelson Cowan's 2001 paper in Behavioral and Brain Sciences puts it near four chunks. Both fit what people do with digits. Splitting 4 8 2 9 1 7 3 into groups, or tying digits to dates and numbers you know, is chunking, and it raises the span you can reach. This page gives you a number from your own runs. It does not compare you with a population and it is not a clinical or diagnostic test.
After each run you see your span, the number you were shown and what you typed, with each wrong position marked as the expected digit over the digit you typed, a plus for an extra digit and a minus for a missing one. Below that is a chart of how many of your past runs ended at each span, from 0 up, with your best and your average. One run varies a lot with tiredness, distraction and luck, so judge yourself on the spread of many runs, not one. The chart keeps your last 100 runs. Only the span of each run is stored, never the numbers shown or the answers typed. You can clear the history at any time.
Say the digits aloud in groups of two or three, or picture them as a phone number. Both are chunking. Playing in a quiet place at the same time of day makes runs comparable. The test is for fun and self-checking. It measures one narrow skill, remembering digits in order for a few seconds, and it says nothing about intelligence or health. The page counts visits with Google Analytics, never your numbers or answers. Clearing your browser data removes the stored history.
The longest number you can see once and type back correctly. If you get 7 digits right and miss 8, your span is 7. If you miss the very first number, your span on this page is 0.
Miller's 1956 paper discussed roughly seven items, digits among them, as a rough rule of thumb, not a population norm, so there is no official 5 to 9 range. Cowan's 2001 review argues for about four chunks when grouping is blocked. This one-trial visual game is not a standardised test and gives no population ranking.
1 second plus 0.5 second per digit. Level 1 shows for 1.5 seconds, level 5 for 3.5 seconds and level 10 for 6 seconds. The shrinking bar under the number shows the time left.
The first wrong answer, including an empty one. A number with a digit swapped, missing or added is wrong. The page then shows the number and your answer with the wrong digits marked.
Chunk the digits. Read 4829173 as 48, 29, 173 or as 482 and 9173. Saying the groups aloud helps too. Chunking raises how much you can hold, but it does not change the small limit on separate items.
No. Only the span of each finished run, such as 7, is kept in this browser, up to the last 100 runs. The numbers shown and your answers are never stored or sent anywhere. Use Clear history to remove the spans.