D-Day Calculator
Calculate the days remaining until or elapsed since a target date.
Result
Enter a target date and calculate the D-Day.
The result is calculated from calendar dates, not times of day.
How It Is Calculated
If today is September 5, 2026 and the target date is September 20, 2026, the result is D-15.
If the target date has passed, elapsed days are shown in D+ format.
How D-Day notation is read
The target date is D-Day. A future date is shown as the number of calendar days remaining, the same date is D-Day, and a past target is shown as days elapsed. Times of day are not part of the calculation.
Useful planning examples
Use the count for an application deadline, release date, exam, trip, or anniversary. If a deadline specifies a time zone or closing hour, check that separately because this page compares dates rather than timestamps.
Frequently Asked Questions
Which date is used as the D-Day reference?
It uses today's calendar date as reported by the user's browser.
What happens if the target date has passed?
The elapsed days are shown in D+ format.