Free interactive tool
Calculate caffeine by half-life
Enter each dose and choose a half-life to estimate how caffeine declines over time. The results also compare three-, five- and seven-hour scenarios.
- Adjustable half-life from 1 to 12 hours
- Combined timeline for multiple drinks
- Estimated times below 50, 25 and 10 mg
What the estimate can tell you
CaffCalc applies exponential half-life decay to each dose, combines the results and shows the estimated amount over time. It is useful for comparing timing choices, not for diagnosing sleep problems or measuring caffeine in your body.