Caffeine Half-Life Calculator
Calculate Caffeine Remaining
Formula
Remaining Caffeine = Initial Amount x (0.5 ^ (hours elapsed / half-life))
Frequently Asked Questions
What is caffeine half-life?
Half-life is the time it takes for your body to eliminate half the caffeine. The average is about 5 hours, meaning 100mg becomes 50mg after 5 hours.
How much caffeine is safe per day?
The FDA recommends up to 400mg per day for healthy adults, roughly 4 cups of coffee. Pregnant women should limit to 200mg.
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