Calculate a strict calendar difference, elapsed days, inclusive dates, completed months, and Mon–Fri dates without DST off-by-one errors.
A quick decision brief for this specific tool
Start and end Gregorian calendar dates from 1900 through 2100, with an optional Mon–Fri-only primary view
Calendar years/months/days, elapsed days, inclusive date count, complete weeks, completed calendar months, inclusive Mon–Fri dates, and 24-hour day equivalents
Strict date-only parsing and UTC calendar-day serial arithmetic, with separate endpoint conventions for elapsed and inclusive counts
Choose your path
Compare two date-only values with explicit elapsed and inclusive endpoint conventions, without daylight-saving drift or a false holiday claim.
Separate elapsed duration from dates occupied by an inclusive schedule.
Enter start/end dates and compare elapsed days, inclusive dates, weeks, months, and calendar breakdown.
Understands why the inclusive count is one greater and can reproduce the result without an average-month approximation.
Count calendar dates across a clock-change weekend without an off-by-one.
Enter date-only values around a daylight-saving transition and inspect the elapsed-day result.
A Saturday-to-Monday range remains two elapsed days and three inclusive dates.
Get a Mon–Fri count without mistaking it for a holiday-aware business calendar.
Enable Workdays only and read the visible counting convention.
Sees the inclusive Mon–Fri count and the explicit statement that public holidays are not removed.
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Add or subtract bounded whole calendar days from an exact Gregorian date without local-time shifts, hidden today defaults, or business-day assumptions.
Elapsed days exclude the start endpoint; inclusive calendar dates include both the start and end.
Inclusive dates = elapsed days + 1Strict YYYY-MM-DD values are converted to UTC calendar-day serials. The tool does not accept times or infer a timezone.
Completed years and months use calendar boundaries. The optional weekday count includes both endpoints and removes Saturday/Sunday only, with no holiday subtraction.
Updated: July 2026
A project manager compares a milestone date with its start and distinguishes elapsed duration from the number of dates occupying the schedule.
Someone checks exactly how many calendar days remain between two date-only bookings without a daylight-saving off-by-one.
A planner uses the inclusive Mon–Fri count for a rough schedule, then moves to a holiday-aware tool before making a commitment.
Compare two Gregorian calendar dates with explicit endpoint rules. See calendar years/months/days, end-minus-start elapsed days, an inclusive date count, and a Mon–Fri-only view that does not claim to remove holidays.