This is Buzz. He means well.
WebMCP-enabled · agent-callable tools
Know when to stop.
Caffeine's half-life means your 3 PM coffee is still whispering to your brain at bedtime. Find your last-call time, track what you've had, and look up any drink — math shown, sources cited, mild judgments included.
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Enter your bedtime to see your latest safe drink time
Threshold: residual under ~50 mg at bedtime. Half the dose clears every half-life. Sources: half-life explainer · cutoff research
Popular right now
(the ones people actually ask us about. we have opinions.)
Brewed Coffee (Drip) 96 mg Espresso Shot 64 mg Cold Brew Coffee 100 mg Starbucks Starbucks Pike Place Roast 155 mg Starbucks Starbucks Cold Brew 205 mg Dunkin' Dunkin' Hot Coffee 180 mg Black Tea (brewed) 47 mg Green Tea (brewed) 28 mg Matcha (traditional bowl) 70 mg Coca-Cola Coca-Cola 23 mg Coca-Cola Diet Coke 46 mg PepsiCo Mountain Dew 54 mg Red Bull Red Bull 80 mg Monster Monster Energy (Original) 160 mg Celsius Celsius (Original Sparkling) 200 mg Living Essentials 5-Hour Energy 200 mg
Track your whole day
Log drinks as you go — see your total against the 400 mg line, your live bloodstream level, and a countdown that tells you when regular coffee is done for the day. Buzz reacts. Sometimes badly.
Plain-English guides
(peer-reviewed, dad-joke-free zone. mostly.)
How Long Does Caffeine Last? The Half-Life, Explained Simply When Should You Stop Drinking Coffee Before Bed? How Much Caffeine Is Too Much? Limits by Age and Situation Caffeine in Coffee vs Tea vs Energy Drinks Cold Brew vs Iced Coffee Caffeine and Sleep What Changes Your Caffeine Half-Life Espresso vs Drip Coffee