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Caffeine Half-Life Calculator (400mg Dose)
Calculate exact caffeine decay and bed-time cutoff for 400mg caffeine dose.
Caffeine Half-Life & Sleep Cutoff (400mg)
Caffeine has a 5-6 hour half-life in healthy adults. Enter the time of your last cup:
People Also Ask (FAQs)
How long does 400mg of caffeine stay in your system?
After 5-6 hours, 200mg remains in your bloodstream. After 10-12 hours, roughly 100mg remains.