What is D-day Countdown?
The D-Day calculator automatically counts the days remaining until any target date and shows it as D-N. It even converts Korean lunar calendar dates (birthdays, memorial days) to solar dates automatically, and supports exams, military discharge dates, 100-day couple anniversaries, and due dates — register up to 20 events with no sign-up.
Future events are displayed as D-N (days remaining), today's events as D-Day, and past events as D+N (days elapsed). With real-time countdown showing days, hours, minutes, and seconds, you can track exact remaining time for up to 20 simultaneous events.
Key Features
Multi-Event Management
Register and manage up to 20 D-day events simultaneously. Sort by date or name for efficient tracking.
Real-time Countdown
Beyond just day counts, get real-time countdown in hours, minutes, and seconds for precise time tracking.
6 Categories
Organize events into 6 categories: General, Birthday, Anniversary, Exam, Travel, and Work for systematic management.
Auto Save
Events are saved automatically when browser storage is available. They do not persist if storage is blocked or the data is deleted.
Copy & Share
Copy D-day information as text to easily share via messenger or social media.
How to Use
- Add Event: Click 'Add Event' and enter the title, target date, and category. You can optionally add a memo.
- Choose Category: Select from General, Birthday, Anniversary, Exam, Travel, or Work to categorize your event.
- Track in Real-time: Registered events are automatically calculated with real-time countdown. Displayed as D-N (future), D-Day (today), or D+N (past).
- Manage & Share: Edit or delete events, and copy as text to share. Use sorting for efficient management.
Use Cases
Exam Preparation
Register D-days for college entrance exams, certifications, and professional tests to plan your study schedule with real-time remaining time.
Anniversary Management
Check the days remaining until relationship anniversaries, wedding anniversaries, and family birthdays. This counter does not send birthday alerts; set any reminders separately in your calendar.
Travel Planning
Add excitement with a countdown to your departure date and systematically manage your preparation timeline.
Project Deadlines
Register work project deadlines, presentation dates, and submission dates to effectively manage your timelines.
Military Discharge Countdown
Register your enlistment and discharge dates to see the days remaining as D-N. Adding the start date also shows a progress bar of your completed service.
100-Day Couple Anniversaries
Enter the day you started dating in the Couple tab and key milestones like 100, 200, and 1000 days are calculated automatically using the Korean convention (day one = the first day).
Due Date Countdown
Register your due date to check the days left until you meet your baby. Adding a start date also displays overall progress.
Lunar Birthdays & Memorial Days
Enter the lunar year, month, day, and regular or leap-month setting to convert that date. Yearly repeat shows the next matching date within the supported range, skipping years without that leap month or day.
Frequently Asked Questions (FAQ)
How many D-days can I register?
You can register and manage up to 20 D-day events simultaneously.
Are registered D-days saved?
Events are saved automatically when browser storage is available and its data remains. You can revisit them on the same device and browser. Blocking storage or deleting the data prevents restoration.
Can I share a D-Day with others?
Use Share URL on an entry to review its dates and details before copying a link. Names and memos are excluded by default, but dates are included. The link is not encrypted. Recipients review and save the event themselves; it does not sync with your existing event.
Can I see past D-days?
Yes, once the target date passes it is displayed as D+N, showing how many days have gone by. Entries are never deleted automatically, so you can keep tracking how long ago an anniversary or event occurred.
Can I register lunar calendar dates like birthdays or memorial days?
Yes. Enter the lunar year, month, day, and regular or leap-month setting to convert that date. Yearly repeat calculates the next matching date within the supported range, skipping years without that leap month or day. It does not send birthday alerts or update an external calendar.
Does the 100-day anniversary count include the first day?
Yes, Korean anniversary counting treats the first day of dating as day one, so the 100th day falls 99 days after the start date. Enter your start date in the Couple tab and milestones are calculated on this basis.
How do I set up an exam D-Day like the Suneung (CSAT)?
Check the Ministry of Education or KICE announcement for your academic year, then add the confirmed date in the Exam category. For example, the 2027 academic-year CSAT takes place on November 19, 2026. Quick Add uses only officially announced dates verified and registered on this site, not a weekday estimate.
Can I see both days left until discharge and my service progress?
Yes, set the discharge date as the target and your enlistment date as the start date. You'll see the remaining days along with a progress bar of your completed service.
Understanding the Korean Lunar Calendar
The lunar calendar remains deeply relevant in modern Korean life. Seollal (설날, Lunar New Year) and Chuseok (추석, the harvest festival) — Korea's two biggest holidays — are determined by lunar dates. Many Koreans still celebrate birthdays on their lunar date, which means the Gregorian date shifts each year.
Other lunar-based observances include Daeboreum (대보름, the first full moon), Dano (단오, the 5th day of the 5th lunar month), and ancestral memorial rites (제사, jesa) held on the lunar anniversary of a family member's passing. Understanding the lunar calendar is essential for tracking these cultural milestones — our D-Day counter supports automatic lunar-to-solar date conversion so you never miss an important date.
Korean Anniversary Culture
100 Days (백일, baegil): Counting 100 days after a baby's birth is one of Korea's oldest traditions. Historically, infant mortality was high, so surviving to day 100 was a genuine milestone. Families celebrate with rice cakes (백설기) and red bean cakes (수수팥떡). Couples also celebrate 100-day relationship anniversaries.
First Birthday (돌, dol): An elaborate celebration where the baby is dressed in traditional hanbok and participates in "doljabi" — grabbing objects that symbolically predict their future. A stethoscope suggests a doctor, a thread represents longevity, and money indicates wealth.
60th Birthday (환갑, hwangap): Marks the completion of one full cycle of the 60-year Chinese zodiac system (combining 10 heavenly stems and 12 earthly branches). Traditionally a grand celebration with a large feast, though as life expectancy has increased, many Koreans now treat the 70th birthday (칠순, chilsun) as the bigger milestone.
Other milestones: Wedding anniversaries follow Western conventions, but Koreans also track monthly "14th" events throughout the year — from Valentine's Day (Feb 14) and White Day (Mar 14) to lesser-known ones like Rose Day (May 14) and Wine Day (Oct 14).
10 Common Korean D-Day Scenarios
A D-Day counter is more than a countdown — in Korea it is deeply tied to daily life, from college entrance exams to anniversaries and military service. Below are the most common D-Day scenarios Koreans track, each with an example reference date.
| Anniversary Type | Reference Date Example | How It's Used |
|---|---|---|
| Suneung (CSAT) | Confirmed example: 2027 academic year, Nov 19, 2026 | Anchor date for high school seniors and re-takers to plan weekly study load |
| Wedding Anniversary | Marriage registration or ceremony date | Use yearly repeat to check the next date; set contact and gift reminders separately |
| 100 / 1000 Days (Couples) | Start date is day 1: day 100 is +99 days; day 1000 is +999 days | Check the listed couple milestones, including 100, 200, and 1000 days |
| Work Anniversary | First day at the company | Auto-calculate 1, 3, and 5-year marks for leave and severance reference |
| Child's Birthday | Actual birth date, not the registration date | Track 100 days (baek-il), first birthday (dol), and lunar birthdays |
| Exams (Civil Service, Certifications) | Written test or interview date | Plan study schedules around fixed annual rounds like civil service or TOEIC |
| Jesa / Memorial Day | Usually on the lunar calendar | Register as lunar so the solar date auto-shifts each year |
| Enlistment / Discharge | Enlistment day / discharge day | Enter confirmed enlistment and discharge dates to see remaining days and progress; the tool does not determine your discharge date |
| Departure / Return | Flight departure date | Manage working holiday, study abroad, or business trips with visa expiry |
| Birthdays | Yours, family, partner | Choose solar or lunar and check the next date; set birthday alerts separately in your calendar |
Entries such as memorial days and lunar birthdays fall on a different Gregorian date every year. Converted with this site's own lunar calendar, Seollal (lunar 1/1) lands on 2026-02-17 and 2027-02-07, Jeongwol Daeboreum (lunar 1/15) on 2026-03-03 and 2027-02-21, Buddha's Birthday (lunar 4/8) on 2026-05-24 and 2027-05-13, Chilseok (lunar 7/7) on 2026-08-19 and 2027-08-08, and Chuseok (lunar 8/15) on 2026-09-25 and 2027-09-15. Register the date as lunar in the D-Day counter and this conversion happens automatically every year.
Privacy Notice
Registered events are calculated here and stored on this device only when browser storage is available; they do not automatically sync across devices. Copying event text or sending an ICS file can share names, dates, and memos. A shared URL contains dates and any name or memo you explicitly include. It is not encrypted, so anyone with the link can read and forward it. Names and memos are excluded by default; review the preview before copying.