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D-Day Calculator

Calculate how many days are left until your target date.

What is a D-Day Calculator?

A D-Day calculator lets you see exactly how many days remain until any important date. Add exams, weddings, trips, anniversaries, or deadlines and watch the countdown in real time. You can manage multiple events at once.

Dates in the future show as D-minus (D-7, D-30, etc.). Today's date shows as D-Day!. Past dates show as D-plus (D+1, D+365, etc.). Enable the yearly repeat option for birthdays and anniversaries so the counter automatically resets each year.

How people use it

Exam countdown

Track days until a big test, certification exam, or college entrance exam so you can plan your study schedule.

Wedding & anniversary

Never miss a wedding date or anniversary again — set a yearly repeat and always know how many days are left.

Travel countdown

Count down to your departure date and use the time to prepare packing lists, visas, and itineraries.

Project deadline

Keep work deadlines and assignment due dates front of mind so nothing sneaks up on you.

Frequently asked questions

How is a D-Day calculated?
The target date minus today's date. If the target is in the future it shows as D-N; if it's today it shows as D-Day!; if it has passed it shows as D+N.
What does D+1 mean?
It means the target date was yesterday — one day has passed since the event.
Can I track recurring dates like birthdays?
Yes. Enable the 'Repeat every year' toggle and the calculator will automatically roll over to next year's date once the current one passes.
Are my D-Days saved?
Yes, they are saved in your browser's localStorage. They will still be there after refreshing or closing the tab, but are not shared across devices or browsers.
How many D-Days can I add?
Up to 10 at a time. Manage exams, trips, and anniversaries all in one place.
What happens when the target date is today?
The counter shows 'D-Day!' in bold to mark the occasion.

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