A web app that tracks caffeine intake and shows how it breaks down in your body over time.

Visit: https://caffeinecalculator.github.io

• Drink Database - Caffeine data from Starbucks, Costa, Dunkin', Monster, Red Bull, and more
• Metabolism Tracking - Shows how caffeine leaves your system using the 5-hour half-life rule
• Timeline Chart - 36-hour graph showing caffeine levels from all your drinks
• Sleep Calculator - Tells you how much caffeine will be in your system at bedtime
• Custom Drinks - Add any drink by entering the caffeine amount manually

• Color-coded Levels:
  • 🟢 Green: Very safe (≤200mg daily, ≤25mg at sleep)
  • 🔵 Blue: Safe (≤300mg daily, ≤50mg at sleep)
  • 🟠 Orange: Warning (≤400mg daily, ≤100mg at sleep)
  • 🔴 Red: Danger (>400mg daily, >100mg at sleep)
• Warnings based on FDA's 400mg daily limit
• Sleep warnings when you have too much caffeine before bed

• Works on Mobile - Responsive design for phones and tablets
• Saves Your Data - Remembers your drinks even after closing the browser
• Auto-Updates - Refreshes every minute to show current levels
• Interactive Chart - Click legend items to show/hide specific drinks

The calculator uses caffeine's 5-hour half-life - meaning half the caffeine is gone every 5 hours:

Remaining = Initial × 0.5^(hours_elapsed / 5)

• Everyone metabolizes caffeine differently (3-7 hour range)
• Doesn't account for body weight or tolerance
• Assumes instant absorption (actually takes 30-120 minutes)

Just visit the GitHub Pages URL - nothing to install.

1. Clone the repo:

   git clone https://github.com/caffeinecalculator/caffeinecalculator.github.io.git

2. Open index.html in your browser

• Plain HTML/CSS/JavaScript - no framework needed
• Chart.js for the graphs (loaded from CDN)
• localStorage for saving data
• Works in all modern browsers

GNU GPL v3 - free software that stays free. See LICENSE for details.