Free interactive tool
When might your caffeine level fall?
Feeling less alert does not mean caffeine has fully cleared. Calculate approximate threshold times from all the drinks you consumed.
- Three practical threshold estimates
- Accounts for multiple doses
- Transparent formula and limitations
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.