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📅 D-day Calculator - Manage Important Dates

Free D-day Calculator to calculate and manage days remaining until birthdays, anniversaries, exams, and important dates!

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No D-days registered.

Add anniversaries, exam dates, and important dates!

📅 What is D-day?​

D-day is a term used to indicate the number of days remaining until or since a specific date.

Key Features:​

  • Visual Management: Check important dates at a glance
  • Auto Calculate: Automatically calculate days remaining or passed
  • Color Coding: Emphasized display as dates approach
  • Local Storage: Safely stored in browser

🎯 Main Features​

1. 📝 Add Events​

  • Title Input: Up to 50 characters
  • Date Selection: Easy selection with calendar
  • Color Assignment: Set unique color for each event

2. 📊 Auto D-day Calculation​

  • D-day: Today!
  • D-7: 7 days remaining
  • D+5: 5 days passed
  • Real-time Update: Auto-calculates when date changes

3. 🎨 Visual Distinction​

  • 🔴 D-day: Today! (Red, with animation)
  • 🟡 Soon: Within 7 days (Yellow)
  • 🟢 Future: 8+ days away (Green)
  • ⚪ Past: Already passed (Gray, semi-transparent)

4. 📋 Event Management​

  • Sort by Proximity: Upcoming dates displayed first
  • Individual Delete: Delete each event individually
  • Clear All: Delete all events at once
  • Permanent Storage: Auto-saved to local storage

📖 How to Use​

Basic Usage​

  1. Enter Title: Enter event title (e.g., Birthday, Exam)
  2. Select Date: Choose target date
  3. Select Color: Choose desired color (optional)
  4. Click Add: Click "Add D-day" button

Advanced Features​

  • Use Colors: Use different colors by category
    • 🔴 Red: Urgent/Important
    • 🔵 Blue: Personal schedule
    • 🟢 Green: Work-related
    • 🟣 Purple: Anniversaries

💡 Usage Examples​

🎓 Students​

  • Exams: Midterm, final exam D-day
  • Assignments: Report submission deadline
  • Vacation: Vacation start countdown
  • Graduation: Entrance, graduation ceremony dates

💼 Professionals​

  • Projects: Project deadline
  • Presentations: Important presentation date
  • Vacation: Vacation start date
  • Performance: Performance review period

💑 Personal​

  • Birthdays: My birthday, family/friends' birthdays
  • Anniversaries: Dating anniversary, wedding anniversary
  • Travel: Travel departure date
  • Goals: Diet goal date, quit smoking start date

🎉 Special Days​

  • Holidays: Christmas, New Year, etc.
  • Events: Concerts, performances, exhibitions
  • Appointments: Doctor's appointment, restaurant reservation
  • Contracts: Contract expiration, renewal date

❓ Frequently Asked Questions​

Q1. Where is data stored?​

It's stored in your browser's local storage. It's not sent to servers and your privacy is protected.

Q2. Does data disappear when I close browser?​

No! It's permanently stored in local storage, so data persists even when you close the browser.

Q3. How many can I add?​

There's no limit. You can add as many events as you want.

Q4. How is D-day calculated?​

It calculates days from today to the target date. Today is D-day, tomorrow is D-1.

Q5. Can I add past dates?​

Yes! Past dates can be added and displayed as D+. (e.g., D+30 means 30 days passed)

Q6. Why specify colors?​

To visually distinguish events. Using different colors by category makes them easier to identify at a glance.

🔒 Privacy Protection​

  • Local Storage Only: Data not sent to servers
  • Privacy Protected: Entered information only stored in browser
  • Secure Management: No external access possible
  • Deletable: Data can be deleted anytime

📱 Browser Compatibility​

  • ✅ Chrome 90+
  • ✅ Firefox 88+
  • ✅ Safari 14+
  • ✅ Edge 90+
  • ✅ Mobile browsers (iOS Safari, Chrome Mobile)

Start managing your important dates systematically now! 📅✨