Half-Life Calculator
How much caffeine is still in your system?
Caffeine decays with a half-life of about 5 hours. Add what you drank and when, and watch the decay curve in real time.
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Drink
Total today0 mg
Estimated Peak—
At bedtime—
Cutoff time—
Calculations assume an average adult caffeine half-life of approximately 5 hours and an estimated absorption period of around 45 minutes. Individual responses to caffeine may vary.