how late can I drink coffe?

A practical guideline is to stop caffeine 8–10 hours before your usual bedtime; if you’re particularly sensitive, leave 12–14 hours. The right cutoff varies from person to person. 1

• Caffeine’s half-life: It’s about 5–6 hours, so caffeine can remain in your system and make it harder to fall asleep or reduce deep sleep even if you feel you can fall asleep normally. 2
• Individual tolerance: People differ in how quickly they metabolize caffeine and how sensitive they are, so use the bedtime guideline as a starting point and adjust based on your response. 3