Calculate a strict calendar difference, elapsed days, inclusive dates, completed months, and Mon–Fri dates without DST off-by-one errors.
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.
This tool is part of these guided projects. Each project provides step-by-step instructions with checklists and all the tools you need in one place.
Tools you might need next
Calculate Gregorian calendar age and UTC-stable elapsed days between two dates, with an explicit February 29 countdown rule and labeled illustrative context.
Convert a clock between explicit fixed UTC offsets, including quarter-hour offsets, with UTC intermediate and calendar-day shift.
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.