See elapsed days and inclusive dates together, or move a date forward or backward by whole days or weeks.
Supported dates: 0001-01-01 to 9999-12-31 in the proleptic Gregorian calendar. This is calendar-date arithmetic, without time zones, times of day or historical local calendar rules.
Dates and holiday lists stay in this page. They are not uploaded or saved. Loading the site still makes ordinary hosting requests and may update the aggregate page-view counter.
Elapsed days measure the distance between the two date boundaries. Inclusive dates count every calendar date you name, including both endpoints. Neither number is automatically the right answer for a booking, deadline or allowance: first check what the relevant rule means by a day.
From Friday 2026-10-16 to Monday 2026-10-19, the elapsed count is 3 days: Friday to Saturday, Saturday to Sunday, and Sunday to Monday. The inclusive count is 4 dates: Friday, Saturday, Sunday and Monday. The same date gives 0 elapsed days and 1 inclusive date.
From 2024-02-28 to 2024-03-01 there are 2 elapsed days and 3 inclusive dates, because February 29 is included. Gregorian leap years are divisible by 4, except century years unless divisible by 400. Thus 2000 is a leap year and 1900 is not.
Adding 2 weeks to 2026-12-25 gives 2027-01-08. Subtracting 1 day from 2024-03-01 gives 2024-02-29. The starting date is the reference point, so adding 1 day means the next calendar date. Weekends and holidays still count.
This tool deliberately accepts days and weeks only. A month can have different lengths, and a year can include a leap day; deciding what to do with dates such as January 31 needs a different rule. It also does not turn date differences into exact hours: a local clock day can change length when the clock changes.
For a project that only runs on selected weekdays, use the business-day planner and supply the actual shutdown dates. For an official deadline, check the contract, employer or authority: endpoint rules, cut-off times, holidays and local law may change the answer.
Technical background: MDN: JavaScript dates, UTC and local time. TinkerMint uses calendar-date arithmetic independent of the device time zone. The proleptic Gregorian model applies the same calendar rules throughout the supported range; it is not a claim about which calendar a place used historically.