Caffeine Cutoff Calculator
That afternoon coffee can still be in your system at midnight. Find out when to have your last one so it does not follow you to bed.
Your evening
Your last coffee
That is about 8 hours before bed. Caffeine has a half-life of roughly 5 to 6 hours, so a late-afternoon coffee can still be in your system at midnight, keeping your sleep lighter even if you fall asleep fine.
Why your last coffee matters
Caffeine has a half-life of about five to six hours, which means half of it is still in your body that long after you drink it, and a quarter is still there after ten to twelve hours. A coffee at 4 PM can leave a meaningful dose in your bloodstream at bedtime.
Even when caffeine does not stop you from falling asleep, it can lighten your sleep and cut into deep sleep, so you wake up less rested without knowing why. Moving your cutoff earlier is one of the simplest changes you can make for better mornings.
Better sleep makes waking up easier, but it does not remove the temptation to snooze. Last Alarm does that part, so you get up on the first try instead of reaching for coffee to undo a rough morning.