I run a free reaction time test and recently hit 10,000 recorded scores. The patterns in the data were surprising.
The Average Is Not What You Think
The commonly cited "average reaction time" of 250ms comes from lab studies with young adults under ideal conditions. Real-world data from people at home, at work, on their phones? Very different.
From 10,000 users:
| Condition | Avg Reaction Time |
|---|---|
| Morning (6-10am) | 287ms |
| Midday (10am-3pm) | 273ms |
| Evening (3-8pm) | 265ms |
| Late night (8pm-2am) | 310ms |
People are fastest in the early evening — that post-work, pre-sleep sweet spot.
What Actually Affects Reaction Speed
The biggest factors, ranked by effect size:
- Sleep — people who reported <6 hours of sleep were 40ms slower
- Age — but the curve is gentler than you'd expect; the big drop happens after 55
- Caffeine — about 15-20ms improvement, but only for the first 2 tests
- Device — mobile users averaged 35ms slower than desktop (touchscreen lag)
Why This Matters
Reaction time correlates with cognitive performance more broadly. A 2019 study found that reaction time variability is a better predictor of cognitive decline than raw speed.
Try the test yourself at checkreaction.com — it takes 30 seconds and gives you a percentile score.
What's your reaction time? Post your score and the time of day you took it — curious if the pattern holds.
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