Date Add / Subtract

Enter a local start date and choose Calendar or Business days. Signed whole values add or subtract; results update immediately. The two tasks are independent, not combined. Reset restores the current date, zero offsets and Saturday/Sunday as skipped days. Small drafts and the selected task survive navigation and reload.

Calendar: years and months determine the target month, then the day clamps to its final valid day; calendar days are applied next, then elapsed hours/minutes. 31 January 2025 plus one month gives 28 February. In Europe/Berlin, 30 March 2024 at noon plus one calendar day gives 31 March at noon (23 hours later); plus 24 hours gives 13:00.

Business days: only the checked weekdays are skipped, with no public holidays. The start date is not counted; zero leaves it unchanged even on a skipped day. An offset requires at least one unselected weekday. Friday 2 May 2025 plus one business day is Monday 5 May when Saturday/Sunday are skipped. Local clock time is preserved at the target date; skipped intermediate DST gaps cannot shift it. Target gaps move forward by the gap and repeated target times choose the earlier occurrence. Directly entered missing clock times are rejected. The browser zone is shown below the output; inputs use positive Gregorian years and minute precision within the browser Date range.