☕ Caffeine Half-Life Calculator
Caffeine's half-life varies significantly between individuals — around 5 hours is a common average.
Enter the amount of caffeine consumed (mg), time elapsed, and caffeine's half-life to calculate how much remains in your body, based on first-order elimination kinetics (the amount halves at a regular interval). Caffeine's half-life varies significantly between individuals, but is commonly cited as around 5 hours on average.
How to use
- Enter the amount of caffeine consumed (mg).
- Enter the time elapsed since consumption.
- Enter caffeine's half-life (hours) — around 5 hours is a common average if unknown.
FAQ
What is a half-life?
The time it takes for the amount of a substance in the body to reduce by half. Caffeine follows first-order elimination kinetics, so the amount in your body roughly halves at each half-life interval.
How long is caffeine's half-life?
Around 5 hours on average for a healthy adult, but it varies significantly based on genetics, smoking, pregnancy, and certain medications. This tool lets you set any half-life to try different scenarios.
Is this result medical advice?
No — this is a simplified calculation based on first-order kinetics, intended for educational reference. Consult a medical professional for specific decisions about caffeine intake.