حساب التواريخ.

Calendar days, not business days. Date range years 0001–9999.

Elapsed days exclude the starting date by default; an inclusive option counts both endpoints. Adding days uses the calendar without daylight-saving shifts. Months and years have variable lengths and are not treated as fixed 30- or 365-day units.

2026-01-01 to 2026-01-31 → 30 elapsed days.