Tools
Caffeine cut-off calculator
Caffeine's half-life averages around five hours — half of your afternoon coffee is still in your system at bedtime maths most people never do. Pick your bedtime and get an honest last-call time.
Average
3:00 pm
last caffeine, 8h before bed — a typical adult metabolism
Caffeine-sensitive
1:00 pm
last caffeine, 10h before bed — slow metabolisers, light sleepers
Barely feels coffee
5:00 pm
last caffeine, 6h before bed — fast metabolisers — still not zero
Honest small print: caffeine half-life ranges from roughly two to twelve hours depending on genetics, medication, pregnancy and liver function — these buffers are starting points, not physiology readings. Decaf, dark chocolate and many teas and sodas carry caffeine too. And if you're cutting caffeine but still sleeping hot, fabric is the next lever — the sleep-temperature guide walks the whole ladder.