Caffeine Cutoff Calculator

The Half-Life Problem Nobody Calculates

Caffeine doesn't wear off when you stop feeling it. It has a half-life of roughly 4–6 hours: a 2pm double-shot (200mg) leaves about 100mg in your blood at 7pm and 50mg at midnight — enough to measurably cut deep sleep in most people, even those who fall asleep easily.

The fix isn't quitting coffee. It's knowing your personal cutoff time: the latest point where your last dose decays below the ~50mg threshold by bedtime. That's exactly what this calculator does.

Why This Matters for Fat Loss and Muscle

• Hunger hormones: one short night raises ghrelin and lowers leptin — you eat an average of 300+ extra calories the next day without noticing.
• Recovery: deep sleep is when growth hormone peaks and muscle repair happens. Caffeine-fragmented sleep blunts both.
• Cortisol: poor sleep elevates next-day cortisol, which drives belly-fat storage and cravings — a vicious cycle that often starts with a 4pm latte.

Practical Rules That Work

• Front-load your caffeine: have your biggest dose within 90 minutes of waking, taper after lunch.
• Watch the stealth doses: pre-workout (150–300mg), energy drinks (80–160mg), and even "refreshing" iced teas count toward your cutoff.
• Swap, don't stop: after your cutoff, switch to decaf or herbal tea — the ritual survives, the half-life problem doesn't.