☕ Caffeine Calculator
Caffeine from coffee, tea and energy drinks
About this calculator
Caffeine hides in coffee, tea, energy drinks, chocolate, and even headache pills. Enter what you've consumed and the calculator totals your milligrams of caffeine, compares it against the 400 mg daily guideline for healthy adults (300 mg if pregnant or breastfeeding), and estimates when it will wear off — caffeine's half-life is about 5–6 hours.
Tip: that 3 p.m. coffee is still half in your system at 9 p.m. — set a personal caffeine cutoff around noon if falling asleep is a struggle.