Caffeine half life and when to stop each day

Caffeine’s half-life is about 5–6 hours. To reduce sleep disruption, stop caffeine 8–10 hours before bedtime; a more sensitive person may need a longer cutoff. 1

• Half and quarter remain: Roughly half the caffeine remains after 5–6 hours, and about a quarter after 10–12 hours. 2
• 10:30 PM bedtime: Stop between 12:30 PM and 2:30 PM—10 to 8 hours before bed. 3
• Sleep quality: Late caffeine can reduce deep sleep even if you fall asleep and stay asleep; it may leave you feeling less restored. 4