How this working memory test works
This test is a 2-back task, one of the most widely used ways to put working memory under load. Press Start test and 30 letters appear one at a time, one every 2.5 seconds. Each letter stays on screen for half a second, then the box goes blank until the next one. That is harder than simply holding a list, which is what the number memory test asks of you.
Your rule: press Match (or the Space bar) whenever the current letter is the same as the letter two steps earlier. In the sequence K – R – K, the second K is a match. In K – K it is not, because that is only one step back.
- 9 of the 30 letters are matches, which is about 30%. The first two letters can never be matches, so 28 letters are scored.
- You can press once per letter, any time until the next letter appears.
- A green frame means you caught a match. A red frame means you pressed on a letter that was not a match.
The whole run takes about 75 seconds. The letter order is generated fresh in your browser each time, so you cannot learn it by heart.
How your score is calculated
A simple percentage of correct letters would be misleading here. Because 19 of the 28 scored letters are not matches, someone who never presses at all would already be "68% correct". So this test uses balanced accuracy:
Score = (matches caught ÷ 9 + non-matches correctly left alone ÷ 19) ÷ 2 × 100
Both halves count equally. Pressing on every letter gives 100% of matches and 0% of non-matches, which is 50%. Never pressing gives the reverse, which is also 50%. So 50% is guessing level, and only real tracking of the sequence moves you towards 100%.
The result card also lists your matches caught, matches missed and false presses. Misses usually mean you lost track of the sequence. False presses often come from reacting to a letter that matched one step back, or three.
The labels on the card are simple bands for this test: 90% or more, 75–89%, 60–74% and under 60%. They are not population norms. Published n-back studies vary a lot in timing, stimuli and scoring, so we do not show a "typical" score. Your personal best and your last results are saved in this browser.
What the n-back task measures
Working memory is the small mental workspace you use to hold information for a few seconds while doing something with it: keeping a phone number in mind as you dial, or following a sentence to its end. Carrying a partial result while you finish a sum is another everyday example, and the mental math test leans on it at its higher levels. In a 2-back task you have to do three things at once: store each new letter, compare it with the one from two steps ago, and drop letters that are no longer needed.
The task goes back to Wayne Kirchner, who described it in 1958 while studying how age affects short-term memory for information that changes quickly. Since then it has become a standard tool in brain-imaging research. A 2005 meta-analysis by Adrian Owen and colleagues pooled n-back imaging studies and found that the task consistently engages areas in the frontal and parietal cortex that are linked to working memory.
Tips for a better score
- Rehearse silently. As each letter appears, say the last two in your head: "K, R… R, K… K, F". When the new letter equals the first of the pair, press.
- Do not chase speed. You have the full 2.5 seconds to respond. A calm press is better than a quick wrong one.
- Watch for one-step lures. A letter that repeats immediately (R – R) is not a 2-back match. Many false presses come from this.
- Warm up. The first run is often the worst, because the rhythm is new. Compare scores after two or three rounds.
- Sleep and attention matter. Working memory is sensitive to tiredness and distraction. Play in a quiet moment for a fair result. To check attention on its own, the attention span test measures how long you stay on task.
Limits of an online working memory test
This is a single, short task with 28 scored letters, so your score will move a few points from run to run. It measures how well you track letters in this 2-back format; it does not cover every kind of memory, and it is not an IQ test. Brain-training games, including n-back, make you better at the game itself; whether that carries over to everyday life is debated in research, so treat improvement here as practice, not proof.
The test is a self-check for curiosity and practice, not a medical or psychological diagnosis. If you notice real changes in your memory, talk to a qualified professional.
More tests of attention, memory and thinking are on the memory and brain tests page.
Sources
- Kirchner, W. K. (1958). Age differences in short-term retention of rapidly changing information. Journal of Experimental Psychology, 55(4), 352–358.
- Owen, A. M., McMillan, K. M., Laird, A. R., & Bullmore, E. (2005). N-back working memory paradigm: A meta-analysis of normative functional neuroimaging studies. Human Brain Mapping, 25(1), 46–59.
Frequently asked questions
What is a 2-back test?
Letters appear one at a time and you respond whenever the current letter is the same as the one shown two steps earlier. It is a version of the n-back task, a standard way to load working memory.
How long does the test take?
About 75 seconds. There are 30 letters, one every 2.5 seconds, and each letter is visible for half a second.
Why is my score not just the percentage of correct letters?
Because most letters are not matches, never pressing would already look like a high score. Balanced accuracy averages the share of matches you caught and the share of non-matches you left alone, so guessing always gives 50%.
What is a good score?
On this test, 90% or more means you tracked the sequence almost perfectly and 50% is guessing level. There is no published average for this exact version, so compare your own results over several rounds.
Is this the same as dual n-back?
No. Dual n-back tracks two streams at once, usually positions and sounds. This test uses a single stream of letters at 2-back, which is easier to start with.
Can n-back training raise my IQ?
Research on this is mixed. Practice clearly makes you better at the n-back task itself, but whether it improves general intelligence or everyday memory is still debated.
Is my data stored anywhere?
Only your score history, in this browser. Nothing is sent to a server, and clearing site data removes it.