Based on the digit span task, with computerized procedures studied by David L. Woods at the University of California, Davis.

Number Memory Test

How many digits can you hold in your head?

The Number Memory Test measures how many digits you can keep in mind at once; the Sequence Memory Test and the Verbal Memory Test do the same for squares on a grid and for words, and the Reaction Time Test and the Typing Speed Test measure how quickly you respond and type. A number appears below for a few seconds and then disappears; you type it back from memory. Get it right and the next number is one digit longer.

One wrong answer ends the run, and your score is the longest number you typed back correctly. Each number is shown for one second per digit, on every device, and phones get the number pad for typing. To take the test, press Start below.

Level 3

Repeating a list of digits is one of the oldest tests in psychology. In 1887 Joseph Jacobs read strings of digits to the pupils of a London school and noted the longest string each could repeat after hearing it once, and that span has been part of intelligence and memory testing ever since. Today it is the digit span subtest of the Wechsler scales: an examiner reads the digits at one a second, and the person repeats them straight away, a little longer each time.

This test keeps the idea and changes the delivery. The whole number appears on the screen at once, for one second per digit, so a seven-digit number stays up for seven seconds: the time the spoken test would take to read it out. When it disappears, you type it back. Every number is new and random, with no repeated digit side by side, no runs like 123 or 975, and no leading zero, and it is never in the page while it is hidden. The display time is taken from the clock, so a slow phone and a fast computer show each number for exactly as long.

Seeing every digit at once changes the task a little. You can read the number in groups, like a phone number, and look at it again before it goes, which a spoken list does not allow; grouping helps in the spoken test too, where a list read out in threes is repeated better than the same list read at an even pace. The one-try rule pulls the other way: the Wechsler test gives two tries at every length, here a single slip ends the run. So scores here are not on quite the same scale as the clinic's, where adults typically repeat about six or seven digits forward, a little fewer with age.

Your score is compared with the scores of tens of thousands of players. The norms of the spoken test would not do, because setting a score from this procedure against them would misplace you by an unknown amount. The players are a self-selected crowd rather than a representative sample, so read the comparison as a rough guide. Every result here is recorded anonymously with the kind of device it was played on, so that in time phones and computers can each be compared on their own.

Short-term memory varies from moment to moment. Tiredness, distraction and a single lapse of attention can end a run early, and with one try per length one unlucky round decides the score. If you want a steadier figure, take the test two or three times and look at your typical score rather than your best. This is a game and a quick measure of how your memory is working today, not a clinical assessment.

References

Jacobs, J. (1887). Experiments on "prehension". Mind, 12(45), 75-79.
Grégoire, J., & Van der Linden, M. (1997). Effect of age on forward and backward digit spans. Aging, Neuropsychology, and Cognition, 4(2), 140-149.
Woods, D. L., Kishiyama, M. M., Yund, E. W., Herron, T. J., Edwards, B., Poliva, O., Hink, R. F., & Reed, B. (2011). Improving digit span assessment of short-term verbal memory. Journal of Clinical and Experimental Neuropsychology, 33(1), 101-111.
Derks, P. L., & Freeman, L. (1966). Recall of simultaneously and successively presented information. Psychonomic Science, 5(2), 51-52.

Frequently Asked Questions

What does the Number Memory Test measure?

It measures verbal short-term memory: how many digits you can hold in mind, in the right order, for the few seconds it takes to type them. It is the same ability that the digit span test examines, although the digits here are shown on the screen all at once rather than read out one by one.

How long is each number shown?

One second for every digit: three seconds for a three-digit number, ten seconds for a ten-digit one. That is the pace of the classic test, which reads the digits out at one a second, so every number gets the time the spoken version would take to present it. The time is measured by the clock, so it is exactly the same on a phone and on a computer.

What is a good score?

Of the tens of thousands of players your score is compared with, the middle player remembers 8 digits, and about one in eight remembers 11 or more. On the classic spoken test, adults typically repeat about six or seven digits.

Does my device change the result?

The timing does not: every number is shown for the same time on every device. Phones get their own layout, with the number pad for typing, and computers use the keyboard. Your result is recorded with the version you played, and the fairest comparison is between results on the same kind of device.

How can I remember longer numbers?

Break the number into groups of two to four digits and say them to yourself, like a phone number, while it is on the screen. Repeating the groups under your breath until you type them helps too. Strategies like these can add a few digits, and being rested and undistracted helps more than anything else.

Number Memory Test

Why Use This Test?

1. Free. The Number Memory Test is free, runs in your browser and works with a keyboard or a phone's number pad.

2. Fair timing. Each number is shown for one second per digit, timed by the clock, so it is on screen for exactly as long on every device, and every number is new and random.

3. Built on research. The task follows the digit span procedure that memory researchers and clinicians have used for more than a century to measure verbal short-term memory.