How the number memory test works
Press Start test and a 3-digit number appears. It stays on screen for 1 second plus half a second per digit, so a 3-digit number is visible for 2.5 seconds and a 10-digit number for 6 seconds. A bar under the number shows how much time is left. When it disappears, type what you saw and press Check answer (or Enter).
If you are right, the next number is one digit longer. If you are wrong, the test ends at once: one mistake is all you get. The page then shows the number next to your answer, with the wrong digits highlighted, and your score is the longest number you typed back correctly. The first digit is never 0, and on phones the answer box opens the number keypad. If you would rather remember words than digits, try the verbal memory test.
Your best score and your last results are saved in this browser only, so you can come back tomorrow and see whether a rested brain does better.
What your score means: the famous 7 ± 2
What you are measuring is close to what psychologists call digit span: the longest list of digits a person can repeat straight after hearing or seeing it. The idea is old. In 1887 Joseph Jacobs tested pupils at a London school this way and noticed that span grows with age.
The best-known number in memory research comes from George A. Miller's 1956 paper The magical number seven, plus or minus two. Miller pointed out that the span of immediate memory, across many kinds of material, sits at around seven items for most adults, with most people falling between five and nine. That is why the comparison band on your result marks 7.
Later research refined the picture. Nelson Cowan (2001) argued that when people cannot group items or repeat them silently, the true limit is closer to four chunks. Seven digits fit because we quietly rehearse them and pack them into groups, the way you remember a phone number as a few short groups instead of a long row of separate digits. Remembering where numbers were on a screen, rather than which digits you saw, is the job of the chimp test.
So as a rough guide:
- Below 5: below the classic 7 ± 2 range. Often a sign of a rushed or distracted round rather than a fixed limit.
- 5 to 9: the range Miller described for most adults.
- Above 9: you are almost certainly chunking well.
Why this is not the same as a clinical digit span
In the digit span subtests that psychologists use, digits are read aloud at about one per second, there are usually two tries at each length, and there is often a backward version as well. Here all digits appear at once on screen, you can scan them in any order, and one miss ends the test. Seeing the whole number makes visual grouping easier, while having only one try makes the score less forgiving. The two numbers are related but not interchangeable, so do not compare your result with a score from a formal assessment. The backward version asks you to rework what you hold, not just keep it, which is closer to what our working memory test measures.
What affects your score and how to improve it
- Chunking. Split the number into groups of three or four as you read it, like a phone number. This is the single biggest boost.
- Saying it silently. Repeating the digits in your head while you type keeps them alive. Background talk or music with lyrics gets in the way.
- Attention and rest. Tiredness, stress and multitasking lower span noticeably from one day to the next.
- Practice, with a catch. In a classic study, K. Anders Ericsson, William Chase and Steve Faloon (1980) trained a student known as S.F. for more than 230 hours. His digit span rose from about 7 to 79 digits, because he linked groups of digits to running times he already knew. His memory for letters did not improve. Practice teaches strategies for one kind of material; it does not enlarge memory in general.
Limits of an online test
This is a self-check for curiosity and practice, not a medical or psychological assessment, and it is not an IQ test. Your score can move by a digit or two between rounds, so judge yourself by your best of several attempts on a calm day. If you notice real changes in your everyday memory, talk to a doctor rather than relying on any online game.
More memory games are on the memory and brain tests page.
Sources
- Jacobs, J. (1887). Experiments on "prehension". Mind, 12(45), 75–79.
- Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Psychological Review, 63(2), 81–97.
- Ericsson, K. A., Chase, W. G., & Faloon, S. (1980). Acquisition of a memory skill. Science, 208(4448), 1181–1182.
- Cowan, N. (2001). The magical number 4 in short-term memory: A reconsideration of mental storage capacity. Behavioral and Brain Sciences, 24(1), 87–114.
Frequently asked questions
What is a good score on a number memory test?
Most adults land between 5 and 9 digits, the range behind Miller's well-known 7 plus or minus 2. Reaching 10 or more usually means you are grouping the digits into chunks.
How long is each number shown?
1 second plus half a second per digit. A 3-digit number stays for 2.5 seconds, a 7-digit number for 4.5 seconds and a 10-digit number for 6 seconds.
What happens if I make a mistake?
The test ends. One wrong answer is enough, and your score is the longest number you typed back correctly before that. Press Try again to start over from 3 digits.
Can I really improve my digit span?
Yes, mostly through strategy. Grouping digits into chunks and repeating them silently helps right away. In a famous 1980 study a student trained for more than 230 hours and went from about 7 to 79 digits, but the gain did not carry over to letters.
Is this the same as the digit span test psychologists use?
No. Clinical versions read digits aloud one at a time and give two tries per length. Here the whole number is shown at once and one miss ends the test, so the scores are not interchangeable.
Does a low score mean something is wrong with my memory?
No. Scores change with sleep, stress and attention, and one round says little. This is a self-check, not a diagnosis. If everyday forgetfulness worries you, talk to a doctor.