📅D-day · Date Calculator
Calculate days between two dates, D-day until a specific date, or the date N days from today. Useful for counting down to exams, weddings, military discharge, anniversaries, project deadlines, dating days, birthdays. Korean lunar calendar not supported.
How to use
- 1Pick a mode from the tabs (D-day / Difference / N days later).
- 2Enter dates and results display instantly.
FAQ
How are leap years handled?+
Uses the JavaScript Date API, which handles Gregorian leap years automatically.
What does 'D-day' mean?+
D stands for 'Day'. D-1 is one day before the event, D+1 is one day after. Originates from military discharge day terminology.
Are lunar dates supported?+
Solar only. For lunar-based D-day, convert with the Lunar ↔ Solar tool first.
Can it calculate down to hours, minutes, seconds?+
Day-level by default. For finer countdowns, a separate tool is needed.
How is the date difference counted?+
Different methods include both start and end, or only one. This tool displays simple day difference.
Track multiple D-days at once?+
One at a time here. For multiple, use a bookmark or calendar app.