Free online calculator
Countdown timer
Track days until any event.
Days until your event
Enter a target date to count down the days — or count up from a past date.
How to use this calculator
- 1
Enter an event name
Type a label for the event — this is optional but helps you keep track.
- 2
Pick the target date
Choose the date you are counting toward or from.
- 3
Read the countdown
The result shows D-N for days in the future, D+N for days in the past, and D-0 for today.
- 4
Bookmark the page
Reload the page any day to get a fresh count — no persistence needed.
Formula
Days until: ⌊(target date − today) ÷ 86 400 000 ms⌋
D-N (N > 0): event is N days in the future.
D-0: today is the event day.
D+N (N > 0): event was N days ago.
Both dates are treated as midnight local time so the count is always whole calendar days.
Worked example
Event on 2026-12-31, today is 2026-04-24:
Milliseconds between the two midnights ÷ 86 400 000 = 251 days → D-251.
Event on 2026-01-01, today is 2026-04-24:
January 1 is 113 days ago → D+113.
FAQ
What does D-Day mean? +
D-Day is a military planning term meaning "the day of the operation." In countdowns, D-0 means today, D-7 means seven days until the event, and D+3 means three days have passed since it.
Does this update in real time? +
The countdown recalculates to today's date each time the page loads. It does not tick down by the second — it counts whole calendar days.
Does the count include today? +
No. If today is April 24 and the event is April 25, the result is D-1. D-0 appears only when today is exactly the target date.
Can I count days since a past event? +
Yes. Enter any past date and the result shows D+N, meaning N days have elapsed since that event.
Can I save a countdown? +
This tool is single-event and stateless — each page load starts fresh. To track multiple events, use the Spendspace app.
About this calculator
This countdown timer calculates the number of days until — or since — any date using the D-Day convention. Use it to track event deadlines, plan trips, count down to celebrations, or measure elapsed time since a milestone.
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