D-Day Countdown Calculator
Enter a target date to calculate the D-day (days remaining or days elapsed) from today. Find out how many days are left until an exam, anniversary, or any date that matters to you.
Frequently Asked Questions
Why is the target day itself shown as D-DAY instead of D-0?
In Korean D-day notation, the target date itself is not treated as a zero point but as the day that has "arrived" — hence D-DAY. The day before is D-1, two days before is D-2, and so on. When the remaining count reaches zero, the target day is written as D-DAY rather than D-0 by convention.
What is the difference between D-1 and D+1?
D-1 means the target date is tomorrow — one day remaining. Conversely, D+1 means the target date was yesterday — one day has passed. The minus sign (−) indicates days remaining; the plus sign (+) indicates days elapsed.
How is D-day used in Korea?
It is widely used to count down to significant events such as the CSAT (College Scholastic Ability Test), other exams, weddings, military enlistment or discharge, and birthdays or anniversaries. "CSAT D-100" marks a countdown to the target; after the event passes, it switches to elapsed notation like "Wedding D+365."
What happens if I enter a past date?
If the target date has already passed, the result is shown in D+ form reflecting the number of days elapsed. For example, entering a date 50 days ago gives D+50. This is useful for checking how many days have passed since an anniversary or milestone.
Is D-day notation an official standard?
No, it isn't defined by any law or formal standard. But the convention of a minus sign for days remaining (D-DAY, D-1) and a plus sign for days elapsed (D+1) is by far the most common usage in Korea, and this calculator follows that convention.
Are leap years handled correctly?
Yes. This calculator computes the actual calendar-day difference between the two dates, so a February 29 falling within the range is automatically accounted for. You don't need to worry about leap years separately.