D-day Calculator - days until or since a target date

How it is calculated

days remaining = target date − reference date (in calendar days)

D-N: the target is in the future; N is the number of days still remaining.
D-DAY: the target and reference date are the same day.
D+N: the target has passed; N is the number of days elapsed after it.
For anniversary-style counting, see “Counting the target as day 1.” It shows Day 1 on the target date and Day 2 one day later.
If the reference date is empty, the device's local calendar date is used. Its time of day does not affect the result.
The day difference uses UTC midnights, so a time zone or daylight saving change does not shift the count.

Examples

1. Days remaining

From 2026-09-24 to 2026-12-25 is 92 days: D-92. The target falls on a Friday.

2. Days since

A target from ten days ago is D+10. Counting the target itself as Day 1 makes today Day 11.

3. Leap-year target

From 2026-09-24 to 2028-02-29 is 1 year, 5 months, and 5 days. February 29, 2028 is a Tuesday.

4. Change the reference date

Use a past reference to see how long remained then, or a future reference to see how much time will have passed.

Please note

The default reference follows this device's date setting. An incorrect device clock changes the “today” result. This tool does not save dates or send reminders.

Privacy

Calculations run in your browser and entered dates are not sent or stored. Read the Privacy Policy for details.

Enter a target date to see the days left (D-N), today (D-DAY), or days elapsed (D+N). You can change the reference date.