By the MyIQTest team · Updated November 2026
What this brain fog test measures
Most brain fog quizzes only ask how you feel. This one measures how you perform right now, with three timed tasks from cognitive psychology.
Reaction time
Your median time to respond to a simple signal over three rounds. The median ignores one lucky or unlucky tap.
Arrow flanker task
Name the direction of the middle arrow while the arrows around it point the other way half the time. Wrong turns and slow answers lower your score.
Digit span
How many digits you can hold in mind and repeat in order, from 4 up to 8. Each round starts only when you are ready.
What your sharpness score means
Your sharpness score runs from 0 to 100, and higher is sharper. Each task is scored on the same scale and the three are averaged, so one slow tap won’t decide the result.
Quick, accurate and a long memory span. You’re on form.
A typical result: quick enough, few slips and a solid memory span.
Slower or less accurate than typical in at least one task.
Below typical in most tasks this time. Try again later and compare.
What is a typical result?
These ranges are a rough guide for adults on a phone or computer. They come from how the test is scored, not from published norms.
| Task | Sharp | Typical | Foggy |
|---|---|---|---|
| Reaction time (mouse) | Under 310 ms | 310–350 ms | Over 390 ms |
| Focus slips (of 10 arrows) | 0–1 | 2 | 4 or more |
| Digits recalled | 7 or more | 6 | 4 or fewer |
Touchscreens add a little delay, so the reaction check allows about 30 ms extra when you tap rather than click, and the arrow task allows more time when you answer with a mouse or finger instead of the arrow keys. These bands match how your result is rated.
What “brain fog” means here
People say “brain fog” about the days their thinking feels slow or scattered. This test doesn’t ask how you feel. It times three things instead: how fast you react, how well you ignore distractions and how much you can hold in mind. That makes it a fair way to compare yourself across days, or with friends.
The research behind the three tasks
- Reaction time is one of the oldest measures in psychology. In the 1880s Francis Galton recorded people’s reaction times, and researchers still compare his figures with modern ones. Most of the gap comes from the delay built into today’s computers (Woods et al., 2015). The reaction time test has the full story.
- The flanker task comes from Eriksen and Eriksen (1974), who showed that letters beside a target slow people down when they call for a different answer. The arrow version used here follows the Attention Network Test (Fan et al., 2002).
- Digit span is the classic measure of short-term memory. Miller (1956) put the typical span at about seven items, give or take two, and grouping digits into chunks is how people stretch it. Try it in the number memory test.
How to get a fair result
- Use the same device and input. A mouse, a touchscreen and arrow keys each add a different delay.
- Find a quiet spot. Notifications and noise turn into focus slips.
- Compare like with like. To compare days, take the test at the same time of day.
- Expect a practice boost. Scores often rise on the second or third try as the tasks become familiar, so compare later results with each other.
- Go for accuracy on the arrows. A wrong arrow costs as much as being about 70 ms slower on every arrow.
Brain fog test FAQ
What does this brain fog test measure?
Three things you can time: how fast you react to a signal, how well you ignore distracting arrows and how many digits you can hold in mind. It doesn’t ask how you feel, so results from different days compare fairly.
How is the sharpness score worked out?
Each task gets a score from 0 to 100, and your sharpness score is the average of the three. Higher is sharper. The bands on this page show what each range means.
What is a good reaction time on this test?
With a mouse, a median under 310 ms counts as sharp and 310 to 350 ms as typical. Taps on a touchscreen get about 30 ms of allowance, because screens add a little delay.
How many digits can most people remember?
George Miller’s classic 1956 paper put the span of immediate memory at about seven items, give or take two. On this test, 6 digits counts as typical and 7 or more as sharp.
Why is my score different each time?
A three-minute session is noisy. Your device, your input (keys, mouse or touch), the time of day and simple practice all move the numbers. Compare results taken the same way, and look at the trend rather than one score.
Does it work on a phone?
Yes. The reaction task allows about 30 ms extra for taps, and the arrow task allows more time for on-screen buttons than for arrow keys.
Is my result saved?
Your past results are kept only in your browser, so the next check can show the change. We also record anonymous scores to improve the test, with no names or emails. The privacy policy has the details.
Is this a clinical test?
No. Like everything on MyIQTest, it gives an estimate for education and entertainment. It is not a clinical or diagnostic assessment.
Sources
- Woods et al. (2015): Factors influencing the latency of simple reaction time, Frontiers in Human Neuroscience
- Eriksen, B. A., & Eriksen, C. W. (1974). Effects of noise letters upon the identification of a target letter in a nonsearch task. Perception & Psychophysics, 16(1), 143–149.
- Fan, J., McCandliss, B. D., Sommer, T., Raz, A., & Posner, M. I. (2002). Testing the efficiency and independence of attentional networks. Journal of Cognitive Neuroscience, 14(3), 340–347.
- Miller, G. A. (1956). The magical number seven, plus or minus two. Psychological Review, 63(2), 81–97.
Like everything on MyIQTest, this check is for education and entertainment. It is not a clinical or diagnostic assessment.
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