Date Difference / Age

Enter two local dates and times and choose Calendar, Elapsed or Weekdays. Results update immediately. Swap dates reverses signed results; weekday counts stay positive. Reset restores a one-week interval ending now. Small raw drafts and the selected view survive navigation and reload.

Calendar: clock times are ignored. Whole months start at the earlier date, clamp to the target month’s last valid day and leave a remainder in civil days. 31 January 2023 to 1 March gives 0 years, 1 month, 1 day; 29 February 2024 to 28 February 2025 gives 1 year. The leading minus applies to the whole calendar span. Whole months omits the remainder. Monday boundaries counts changes of Monday-based weeks, not completed seven-day periods or ISO week numbers.

Elapsed: actual signed time from From to To, including daylight-saving changes. Days are 24 hours and weeks seven such days; output rounds to at most three decimals. Weekdays: every Gregorian civil date from the earlier to the later date, including both ends, regardless of clock time. Monday–Friday is a weekday count, with no public holidays. One date counts once even when elapsed time is zero. Inputs have minute precision and positive Gregorian years within the browser Date range. The browser time zone is shown below the result; missing local DST times are rejected and repeated times use the earlier occurrence.