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Digit span: the number memory test, played as a game
Digit span is the longest string of digits a person can repeat back in order straight after seeing or hearing it. In adults it sits around seven digits, give or take two. Psychologists have used it since the late 19th century to study short-term memory.
Spanrun turns it into a game: digits flash by, you type them back, and every right answer adds one more. This guide gives the exact rules, the methods that help you hold more digits, what we measured on the game's generator, and what research does and does not say about training. Spanrun is a game: it does not replace a memory assessment.
In short
- Genre: a single-player memory game, built on the forward digit span test.
- Goal: type back the longest string you can, in order.
- Lengths: 4 digits in the first round, one more per right answer, 30 at most.
- Pace: one digit every 0.8 seconds, visible for 0.6 seconds.
- Lives: two. The second mistake ends the game.
- Daily digits: the same string for everyone, renewed at midnight, Paris time. Your first try is ranked, later ones are practice, up to 10 games a day.
- Free run: new digits every game, up to 200 a day, with your best score of the day ranked.
- Account: none. Your first game gives you a guest name.
- Devices: computer, phone or tablet, with JavaScript on.
The rules of Spanrun
A round
You start the round when you are ready. The digits appear one at a time in the same spot, then a question mark hands over to you. Type the string back: your answer is sent automatically as soon as you have entered as many digits as were shown.
Right or wrong
A right answer moves you up to the next length. A wrong answer costs a life, shows you the correct string and replays the same length with different digits. Lost lives do not come back, even after several good rounds.
Edge cases
- Before the question mark, keys do nothing: anything typed while the digits run is lost.
- The last digit is final. You can delete until the string is complete, but not after.
- Leaving or reloading the page during a round counts as a mistake when you come back.
- There is no time limit on typing when you play solo: you never lose a life for thinking.
- Two mistakes at 4 digits give a score of 0. Getting 30 digits right ends the game, since no longer round exists.
- Never the same digit twice in a row: the generator forbids it, because two equal digits in a row would read as one on screen.
The score
Your score is your span: the longest string you got right. On equal spans, the shorter answer time goes first. It adds up, for right answers only, the time between the end of the digits and your last keystroke.
Holding more digits
Up to 6 digits: your inner voice
Digits you read can be turned into sounds that you repeat silently: Baddeley and Hitch's model calls this the phonological loop. So say the digits to yourself as they appear, without dragging them out. Avoid talking during a round: saying something else aloud blocks that rehearsal and memory for verbal items drops.
Around 7 to 9 digits: groups
Seven separate digits are seven items. Three groups are only three. Here is the same string, 8 1 6 3 9 2 5, before and after splitting it, into a group of three and then two groups of two:
Since each round adds a digit, decide in advance how you will split each length, say 3-2-2 at 7 digits and 3-3-2 at 8: a fixed plan saves you from thinking while the digits run. A 1972 mathematical analysis by Dirlam judged groups of three or four items the most efficient. At 800 milliseconds a digit, mark each group with a tiny pause in your inner voice, as you would with a phone number.
Beyond that: give the groups a meaning
A group only really counts as one item if it means something to you. A string 1 9 8 4 becomes a year, 1 2 3 the start of a count, 4 2 an age. That was the method of the student known as S.F.: he turned digits into running times, ages and dates, and went from 7 to 79 digits in more than 230 hours of practice, spread over about two years.
Patterns to look for
Some strings hand you a ready-made group. In this one, the two 7s sandwich a 2, then 4 and 5 follow each other as in counting (marked squares):
A false memory you can catch
If you remember "3 3", one of them is wrong, since two equal digits never follow each other. That does not give you the answer, but it does warn you about a mistake you can see coming.
Getting faster
- Aim for one more digit first. A round you get right beats any time: the clock only separates two equal spans.
- Breathe between rounds. When you play solo, nothing runs until you start the next round. Take a moment to settle before you go again.
- Type as soon as the question mark appears. Your inner voice fades quickly, and a typing slip costs as much as a memory lapse.
Benchmarks: what the numbers say
The generator's strings
We drew 20,000 strings per length with Spanrun's generator in November 2026. Each digit makes up about 10% of the total: none is favoured.
| Length | All different | One digit at least 3 times | Sandwich (7 2 7) | Two digits in sequence (3 4, 8 7) |
|---|---|---|---|---|
| 4 | 68.6% | 0% | 21.3% | 48.7% |
| 5 | 45.9% | 1.2% | 29.9% | 58.5% |
| 6 | 25.7% | 4.5% | 37.8% | 66.9% |
| 7 | 11.2% | 10.7% | 44.3% | 73.6% |
| 8 | 3.7% | 20.1% | 51.2% | 78.3% |
| 9 | 0.9% | 30.9% | 56.2% | 82.3% |
| 10 | 0.1% | 43.8% | 61.2% | 86.2% |
| 12 | 0% | 69% | 69% | 91.5% |
What you can do with this: at 7 digits, nearly nine strings in ten contain a digit that comes back, and on average only 5.56 different digits appear. So do not treat a digit you have already seen as your own mistake: note it, it is a landmark. At that length, three strings in four also offer a pair in sequence, an effortless group.
How long a game takes
Games are short. With no mistakes, the digits run for 17.6 seconds in total to reach 7 digits (4 rounds), 57.6 seconds to reach 12 (9 rounds) and 2 minutes 43 to reach 20 (17 rounds). Add your typing time and your breaks.
What the second life is worth: a simulation
This table measures no real player. It is a model: we had a fictional player play 20,000 games per number of lives, on the game's real logic, with success odds we picked ourselves. This player always succeeds below 7 digits, one time in two at 7, one in four at 8, one in sixteen at 9, and never beyond. Only the gap between the rows matters.
| Lives | Simulated average span | Ends on 6 | Ends on 7 | Ends on 8 | Ends on 9 |
|---|---|---|---|---|---|
| 1 | 6.63 | 49.7% | 38% | 11.7% | 0.6% |
| 2 (the game) | 7.05 | 25.7% | 46% | 25.7% | 2.5% |
| 3 | 7.35 | 12.7% | 44.5% | 37.8% | 5.1% |
In this model, the second life adds 0.42 digits on average and halves the games that end on 6. It also shows that a player whose level does not change ends on 6, 7 or 8 depending on the game, so one bad score is not enough to say your level has dropped. Judge your progress over several days.
Rough figures
The reference is still "seven, give or take two": that is the adult average in reviews of memory span, from tests that often present one item per second. Spanrun runs a little faster and follows no clinical protocol, so do not compare your score with a norm. When rehearsal and grouping are prevented, central capacity falls to 3 to 5 items in young adults, according to Nelson Cowan.
In memory competitions, the closest event is spoken numbers, read at one digit per second. Guinness gives 547 digits, by Ryu Song I, in Wuhan in December 2019. Wikipedia gives 660 digits, by Hu Xueyan, at the 2024 WMSC world championship. The two lists, checked on 7 November 2026, disagree, so take these numbers as rough figures. They do not compare with your score: the event is spoken, Guinness allows 20 minutes for recall, and the case of S.F. shows what a learned method can change.
The history of digit span
Spanrun is a Neurostim game: it takes the test's principle, a growing string to repeat in order, and adds two lives, a clock and a shared string every day.
- 1887: J. Jacobs, curious about the memory of London schoolchildren, publishes "Experiments on Prehension" in the journal Mind. He reads them lists of digits and notes how many they can repeat in order.
- 1905: Binet and Simon take the test into their early intelligence scales.
- 1955: David Wechsler publishes the WAIS, whose later versions place digit span in the working memory index.
- 1956: George Miller publishes "The Magical Number Seven, Plus or Minus Two": span is counted in chunks, and recoding information lets you fit more in.
- 1974: Alan Baddeley and Graham Hitch propose their model of working memory, with the phonological loop.
- 1980: K. Anders Ericsson, William Chase and Steve Faloon publish the case of S.F. in Science ("Acquisition of a Memory Skill").
- 1991: the first World Memory Championships, started by Tony Buzan and Raymond Keene.
Frequently asked questions
What is a digit span test?
A digit span test measures the longest string of digits you can repeat without error right after hearing or seeing it. It starts short and gets longer until you fail. It is the most widely used memory span task, and is used to estimate how many numbers working memory can hold.
How many digits can the average person remember?
The average healthy adult can repeat about seven digits, with most people falling between five and nine. Span also depends on word length: it is higher for short words than for long ones, which partly explains differences between languages.
What is the difference between forward and backward digit span?
Forward span asks you to repeat the digits in the order given; backward span asks you to repeat them starting from the last one. Backward is harder, because you have to manipulate the information and not just hold it. Spanrun is forward only: you always type digits in the order they appeared.
Does digit span measure working memory?
Yes, digit span is a standard measure of how much numerical information working memory can hold, though only part of what working memory does. Psychologists also link it to the phonological loop, the inner voice that rehearses sounds. Spanrun uses the same principle as a game, so its score is not a clinical measurement.
Is digit span linked to IQ?
Digit span is one part of some IQ tests, but a digit span score alone is not an IQ. In the Wechsler adult scale it is one subtest among many, in the working memory index. Spanrun calculates no index and no IQ, and the number of digits you reach cannot be converted into one.
Can Spanrun tell me if I have ADHD?
No, Spanrun cannot tell you whether you have ADHD or any other condition, because it is a game with no clinical norms or protocol. A score here depends on practice, method, tiredness and luck on the day. If your attention or memory worries you, talk to a doctor or a qualified psychologist.
How can you remember numbers better?
Split numbers into groups of two, three or four and repeat them silently, as with a phone number. Then give the groups a meaning whenever you can: a date, an age, a running time. Decide on your split before the round, and avoid talking while the digits run, because that blocks rehearsal.
What is the digit span world record?
There is no single digit span record, but the closest event is spoken numbers at memory competitions, read at one digit per second. Guinness lists 547 digits by Ryu Song I in 2019, while Wikipedia lists 660 by Hu Xueyan in 2024, both checked in November 2026. The two lists disagree, and the event is spoken, so these figures do not compare directly with a Spanrun score.
Do number memory games improve working memory?
You will probably get better at the game itself, but nothing guarantees an effect on your memory in daily life. A study of 11,430 participants found no transfer to untrained tasks, and a 2016 meta-analysis concluded that gains are short-term and specific to the exercise. Play because it is fun, not as a treatment.
Is there a free number memory test online?
Yes, Spanrun is a free number memory game you can play online, with no account and nothing to install. Your first game gives you a guest name, ranked like members, and you can create an account later and keep your results. For a change, try Glowback for positions or Memo Chars for symbols.
Sources
- Millisecond, Digit Span; Gorilla, Digit Span, checked on 7 November 2026.
- George A. Miller, The Magical Number Seven, Plus or Minus Two, Psychological Review 63, 1956, pp. 81-97.
- Nelson Cowan, The Magical Mystery Four, Current Directions in Psychological Science 19 (1), 2010, pp. 51-57.
- Wikipedia, Memory span, Chunking, Baddeley's model of working memory, Wechsler Adult Intelligence Scale, Corsi block-tapping test.
- Adrian M. Owen et al., Putting brain training to the test, Nature 465, 2010, pp. 775-778.
- Monica Melby-Lervåg, Thomas S. Redick and Charles Hulme, Working memory training does not improve performance on measures of intelligence or other measures of "far transfer", Perspectives on Psychological Science 11 (4), 2016, pp. 512-534.
- K. Anders Ericsson, William G. Chase and Steve Faloon, Acquisition of a memory skill, Science 208 (4448), 1980, pp. 1181-1182.
- Guinness World Records, Most spoken numbers memorized at a rate of 1 per second, and Wikipedia, World Memory Championships, checked on 7 November 2026.
Your turn
Today's Spanrun challenge is the same for everyone until midnight, Paris time. No account needed: you get a guest name with your first game.
Games of the same kind
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