What Date Was N Days Ago?
Instantly find the date a given number of days before (past) or after (future) any base date, complete with the day of the week and ISO week number.
Input
Result
Enter a base date and the number of days.
How it works
- Pick a base date, then enter a number of days and choose before (past) or after (future) to see the matching date along with its day of the week.
- Each result also shows the Japanese era and the ISO 8601 week number, so you can check the calendar year and week at a glance.
- Enter the number of days as a whole number of 0 or more. The tool does not count the base day as day 0; it returns the date exactly that many days away from the base date.
- Leap years and month-end rollovers are handled automatically, so even long spans that are easy to miscalculate by hand come out accurate.
- The Japanese era follows the modern era system; at an era boundary the date is shown using the newer era name.
- You can share the result on X (formerly Twitter). Handy for confirming deadlines or counting backward from an anniversary.
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