Free Reaction Time Estimator

Estimate how your reaction time is affected by sleep, caffeine, age, and fatigue compared to a baseline.

years
hours
mg

One coffee ~ 100 mg

hours

Estimated Reaction Time

203 ms

Age-Based Baseline208 ms
Total Adjustment-5 ms

Estimated Reaction Time vs Age

Reaction Time Estimation

Average visual reaction time is about 200-250 ms for young adults.

Factors Affecting Reaction Time

FactorEffect Age+1.5 ms per year above 25 Sleep loss+15 ms per hour below 7 CaffeineUp to -20 ms improvement Fatigue (>14h awake)+10 ms per hour

Practical Impact

At 60 mph, each 100 ms adds about 8.8 feet of stopping distance.

Example Calculation

A 30-year-old, 7 hours sleep, 100 mg caffeine, 8 hours awake.

  1. 01Base RT = 200 + (30 - 25) x 1.5 = 207.5 ms
  2. 02Sleep penalty = 0 (7 hours is adequate)
  3. 03Caffeine benefit = 100 x 0.05 = -5 ms
  4. 04Fatigue = 0 (8 < 14)
  5. 05Total = 207.5 - 5 = 203 ms

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