Caffeine Half-life Calculator
Model caffeine remaining after elapsed time using an initial amount and a user-chosen half-life.
How to use
- Enter initial caffeine in mg and elapsed hours.
- Choose a positive assumed half-life and calculate remaining amount, percentage, and decrease.
Capabilities and scope
The half-life is editable rather than fixed at five hours, with 5 h and 15 h example shortcuts.
How it works
remaining=initial×0.5^(elapsed/halfLife).
Example
100 mg after 5 hours with a 5-hour half-life leaves 50 mg in the mathematical model.
Interpretation
Initial amount and elapsed time must be non-negative; half-life must be positive.
Useful for
- Compare theoretical decay under different half-life assumptions
- Explore a simple time-decay model between caffeine intakes
Before you use it
- It does not estimate blood concentration, alertness, safe intake, or fitness to drive, and individual half-life varies substantially.
Frequently asked questions
Is the 15-hour shortcut a medical recommendation for pregnancy?
No. It is only an example of a longer half-life assumption, not a personalized medical value.