Guides
Everything on this site runs on half-life math and published research. These guides explain both without the jargon.
How Long Does Caffeine Last? The Half-Life, Explained Simply ~5 hours When Should You Stop Drinking Coffee Before Bed? 6+ hours How Much Caffeine Is Too Much? Limits by Age and Situation 400 mg Caffeine in Coffee vs Tea vs Energy Drinks 96 / 47 / 160 Cold Brew vs Iced Coffee ~100 vs ~96 mg Caffeine and Sleep ~1 hour What Changes Your Caffeine Half-Life 2–12 hours Espresso vs Drip Coffee 64 vs 96 mg