GORILLA CAFFEINE

Half-Life Calculator

Log what you drank and when, set your personal half-life, and see exactly how much caffeine is still in your system at bedtime — with the time it finally clears the sleep threshold.

1 · YOUR CAFFEINE

Add each drink and the time you had it. Energy-drink figures come from our verified Canadian-market data; coffee/tea are standard references.

  • 190 mg · Large coffee (475 mL)3:00 PM

2 · YOUR METABOLISM

Caffeine half-life varies a lot. A healthy adult averages ~5–6 h, but smoking can roughly halve it, while pregnancy, oral contraceptives and some medications can double it — which is why this is adjustable.

5.5h

3 · RESULT

Sleep threshold

Peak in your system

190mg

Still in you at 11:00 PM

69mg

0501001502003:00 PM5:00 PM7:00 PM9:00 PM11:00 PM1:00 AM+1d3:00 AM+1dSleep threshold 50 mgbed

Your caffeine drops below the 50 mg sleep threshold at 1:36 AM (next day). At your 11:00 PM bedtime you'll still have ~69 mg on board — above the threshold, so it may delay or fragment your sleep.

Health Canada advises a maximum of 400 mg of caffeine per day for adults (200 mg if pregnant). Not recommended for children, adolescents, pregnant or breastfeeding people, or those sensitive to caffeine or with heart conditions.

Estimates only. Caffeine pharmacokinetics vary widely between individuals (genetics, liver enzymes, smoking, pregnancy, medications). The model assumes instant absorption and first-order (exponential) elimination. Not medical advice.