Reaction time test: how alert are you right now?
As soon as the number appears, tap – as fast as you can. For three minutes, at irregular intervals. It measures not just your reaction time but above all your lapses: the most reliable sign of fatigue.
How it works
- 1Sit still, finger over the key or screen.
- 2Start – after a random pause a counter appears.
- 3Tap immediately – on the area or with the space bar. Tapping too early counts as a false start.
- 4Keep going for three minutes – the length is what makes the test sensitive.
- 5Result: your median reaction time, lapses from 355 ms – the threshold of the 3-minute version – and your best score.
The test from sleep research
The Psychomotor Vigilance Test (PVT) was developed by Dinges and Powell (1985) and is the standard for measuring fatigue – in shift work or sleep deprivation, for example. The 3-minute version used here was validated by Basner and colleagues (2011).
What to do with it
Below 280 milliseconds you are wide awake, up to about 340 in the normal range. More lapses than usual mean: this is not a good moment for hard material. Measure in the morning and afternoon – you find your alert hours and put the demanding tasks there. Background in the focus guide.
Sources: Dinges & Powell 1985; Basner et al. 2011
Frequently asked questions
What is a good reaction time?
As a guide: below 280 ms wide awake, up to 340 ms normal, above that rather tired. Comparing with your own measurements says more.
Phone or laptop?
Both work, but don’t mix them: screens and keyboards have different delays.
What does PVT stand for?
Psychomotor Vigilance Test – a test of sustained attention.
More for “Concentration”
- A focus timer that grows with youA study timer that lengthens your attention span step by step. Note distractions instead of giving in. Free in your browser, no account.
- Schulte table onlineTap the numbers 1–25 in order as fast as you can: the Schulte table free in your browser, with timing and history.
- N-back test onlineDoes the square from n steps ago light up again? N-back free in your browser, the level adapts – with an honest look at the research.
- Stroop test onlineThe classic of attention research: pick the ink colour, not the word you read. Stroop test free in your browser, with interference measurement.
All exercises: Concentration →
Exercises are no substitute for help if you've been feeling bad for a while. Talk to your university's counselling service. In a crisis: call your local emergency number or a crisis line in your country.