Countdown (D-Day)
Days until or since a date
Input
Result
Everything is calculated in your browser. The dates you type are never sent to a server.
How to use
Counts how many days are left until a date, or how many have passed if it is behind you. You can choose whether the start date counts as day one, so the result matches whatever convention your school or workplace uses. Dates you enter are never uploaded.
When to use it
- Counting down to an exam, a deadline or a discharge date.
- Checking how long ago an anniversary or event was.
- Working out "day N" for a course or a work period.
How to use it
- Pick the target date — past dates are fine too.
- The base date is normally today; the Today button fills it in.
- Choose the counting rule: base date is day one, or the next day is.
- The days remaining or elapsed appear immediately.
Good to know
- The rule shifts the answer by one day. Many places count today as day one; others start from tomorrow, so both are offered.
- The calculation is by calendar date. Hours and minutes are ignored, so the same day gives zero.
- Everything is computed in your browser and the dates are stored nowhere.
- The result follows this device's clock; if its date is wrong, so is the answer.
Frequently asked questions
My D-day is off by one.
Different counting rules. Military and school counts usually include the start date, while a plain countdown counts only the days remaining. Switch the rule on screen to see both numbers.
What if the target is today?
It says "that is today" rather than a number, because whether today is day one or day zero depends on the rule you chose.
I need hours as well.
Elapsed hours and minutes are the job of the elapsed time tool. The D-day counter works in whole calendar days.
Can it skip weekends and holidays?
The date difference tool also shows the count with weekends removed. Public holidays differ by country and year, so they are not deducted — a plausible but wrong number would be worse than none.