How to use this calculator
Choose add or count, set weekend weekday numbers, and enter any holiday dates yourself.
Formula and method
A business day is a date outside the selected weekend set and user-entered holidays. Add mode excludes the start date; count mode counts (start, end].
Worked example
Starting Monday 2026-10-05 with Saturday–Sunday weekend and no holidays, adding five business days reaches Monday 2026-10-12. Counting to that date gives five.
Assumptions and supported scope
No built-in national holiday calendar or timezone cutoff. At most 10,000 days to add, 30,000-day count range and 366 entered holidays.
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