Free tool · winter slump edition · updated November 2026
Stop guessing your focus. Start measuring it in sixty seconds.
A free focus test that runs in this page: twenty-four go/no-go trials, a live counter, your reaction time to the millisecond, and an honest note about what that number is and is not. Then the longer read on why 3 pm in December feels like fog, and the four-minute game we make for it.
Press Start. A square flashes 24 times. Tap the big button for blue, do nothing for red. About a second each.
Timing is measured in your browser and is approximate. This is a sketch of a go/no-go task, not a clinical test, and it stores nothing.
The afternoon slump has a reputation for being a character flaw, and it is mostly a clock. NIOSH's own training on long work hours describes the early afternoon as a time when the circadian rhythms that promote wakefulness dip while the pressure to sleep keeps building. In December the morning light that would prop that rhythm up arrives late and leaves early. So you sit at your desk at 3:10 pm, read the same sentence three times, and conclude that you are bad at your job. You are not. You are in a trough.
What a free focus test gives you is a number for the trough. Not a diagnosis, not a rating of your brain, just a way to see that your reaction time at 3 pm is slower than at 10 am and that you tapped on two red squares you would have left alone this morning. That is useful for one reason: it turns a vague feeling into something you can act on, which usually means standing up, going outside into whatever light there is, and coming back.
The slump is not a character flaw. It is a clock, and in December the clock runs on less light.
Honest limits, before the app
It is a game.SkillArena's listing says its ratings describe performance in its own games and are not an IQ score or a medical, psychological or clinical assessment. The test above is even less than that.
No training claim.We do not claim that four minutes a day makes you better at anything except the games. Research on brain-training transfer is thin; we have said so on another page and the position has not changed.
Game Center is optional and public.Leaderboards show your Game Center name. They are off unless you turn them on and need a connection.
New app, iPhone and iPad, iOS 18.Version 1.1 from September 2026. Few reviews yet.
Questions people ask the test
What is a go/no-go test?
A simple attention task: a signal appears, you respond to most of them (go) and withhold the response to a rarer one (no-go). It measures two things at once: whether you respond fast enough when you should, and whether you can stop yourself when you should not. The lab version is the Sustained Attention to Response Task (Robertson et al., 1997); the one above is a 24-trial browser sketch of the idea, and SkillArena's Deep Focus is a 30-trial version.
Is this free focus test accurate?
Accurate enough to notice a slump, not accurate enough to diagnose anything. Browser timing, screen refresh and the finger you use all add noise. Run it twice at 10 am and twice at 3 pm and compare your own numbers; comparing yourself with a table of other people is where it stops being useful.
Why do I lose focus around 3 pm?
Partly biology. NIOSH's training materials on work hours describe an afternoon period when the circadian rhythms that promote wakefulness dip while sleep pressure keeps building. Short daylight in December removes the morning light that props the rhythm up, which is one reason the slump feels worse now than in June. The fix is not an app; it is light, movement and sleep. The app is a four-minute way to notice.
What does SkillArena actually claim?
Per its listing: it is a game, ratings describe your performance in SkillArena's own games, and they are not an IQ score or a medical, psychological or clinical assessment. We like that sentence and we are not going to contradict it here.
Is SkillArena free?
Yes. The listing describes it as a free skill game with no account and no ads, all games working offline; optional Game Center leaderboards need a connection. There is no subscription mentioned in the listing.
How long is a session?
The Daily Arena is four games in about four minutes; Quick is about two and Extended about eight. Timers pause if you leave the app mid-round, per the release notes.
What the four minutes look like
Today's Arena: four games, about four minutes.Deep Focus: the 30-trial go/no-go, which the test above is a sketch of.
Tuesday, 3:10 pm, made up but familiar
3:10 pmThird read of the same paragraph. You run the test above instead of the fourth read: 21 hits, two false alarms, 412 ms. This morning it was 24, zero, 340. The number is the permission slip.
3:14 pmOutside. Grey, but light. Eleven minutes round the block, no phone.
3:30 pmBack at the desk. Daily Arena, Quick: two minutes, four games. The point is not the rating; it is that the games demand the same attention the paragraph does, and they are easier to start.
3:33 pmThe paragraph, read once.
Play free on iPhone
SkillArena: Focus Training. Four short games a day, thirteen in the arena, a 30-trial Deep Focus go/no-go, ratings explained in full. Free, no account, no ads, offline.
Robertson, I. H., Manly, T., Andrade, J., Baddeley, B. T., & Yiend, J. (1997). ‘Oops!’: Performance correlates of everyday attentional failures in traumatic brain injured and normal subjects. Neuropsychologia, 35(6), 747–758. doi:10.1016/S0028-3932(97)00015-8 (the Sustained Attention to Response Task, the lab form of go/no-go).
SkillArena: Focus Training on the App Store, listing and release notes read 4 November 2026 (version 1.1.0): Daily Arena lengths, Deep Focus, ratings statement, free and offline, Game Center.
General information. The in-page test is a demonstration and stores nothing; it is not an assessment of attention, health or ability.
Test your attention span at home (shift workers)Test your attention span at home when you work nights or sleep badly: a sleep-debt check, what a 5-minute attention test can tell you, and when to re-test.
