Caffeine mg: Half-life Tracker

Caffeine mg is a one-tap caffeine tracker that visualises remaining body caffeine and the time it drops below a sleep-friendly threshold using a half-life decay model. "Can I have one more coffee this afternoon and still sleep tonight?" — that's the question this app answers. ■ Who it's for - Daily coffee or energy drink consumers - People whose afternoon caffeine affects sleep - Users who prefer no ads and one-time purchases - Login-free tracking with caffeine records stored on device ■ Main features - 50+ preset drinks (coffee, energy drinks, tea, etc.) - Custom drinks with caffeine content and serving size - Tap to log "now", long press to set the time - Today's total intake and remaining allowance (400mg default) - Half-life decay simulation - Home screen widget for one-tap logging - Siri / Shortcuts support - Last 7 days of history ■ iOS 18 features (Pro) - Live Activity + Dynamic Island for body caffeine + sleep-friendly time - Lock Screen Control + Control Center for one-tap logging - Action Button on iPhone 15 Pro and later - Half-life simulation chart ■ Pro (one-time, JPY 370) - Unlimited custom drinks - Live Activity / Dynamic Island - Lock Screen Control - Action Button integration - Full history + CSV export - Medium / Large widgets ■ Why we made it - Free to start (50+ presets + 3 custom drinks) - No login, no account - Caffeine records stay on device; anonymous usage events are optional - No subscription. Pro is one-time only. - Zero ads. ■ Science - Daily upper limit 400 mg (WHO / FDA / EFSA / Health Canada / Japan MHLW Sleep Guidelines 2023 consensus) - 50 mg "sleep-friendly residual" threshold per Japan MHLW Sleep Guidelines 2023 - Default half-life is 5 hours (individual range 3-7 hours) - All thresholds adjustable in Settings ■ Requirements - iOS 18.0 or later (for Live Activity / Lock Screen Control / Action Button) This app is intended as a caffeine intake tracker. It does not provide medical advice, diagnosis, drug-interaction checks, or individualised guidance for pregnant users, users with cardiac conditions, etc. Please consult a doctor or pharmacist for health decisions.