Business Days Calculator · Guide

Business Days vs. Calendar Days

Calendar days count every date. Business days count only dates that match a defined working calendar.

Calendar days

A calendar-day range includes every date in the range: weekdays, weekends, holidays, and other closures.

Business or working days

A business day depends on a rule. In this app, a date counts only when its weekday is selected as working and it is not listed as an excluded date.

Monday through Friday example

Monday October 19, 2026 through Friday October 23, 2026 contains five calendar days and, with the default Monday-Friday workweek and no exclusions, five business days.

Weekends are configurable

Not every organization uses Saturday and Sunday as its non-working days. Configure Working weekdays to match the calendar you actually need.

Holidays and closures

Public holidays differ by jurisdiction and organization. The calculator does not maintain an automatic holiday database; add applicable dates as exclusions.

Inclusive and exclusive endpoints

Some workflows count the Start date, some do not. Count mode exposes Include start date and Include end date so the assumption is explicit.

Adding business days

The Base date is day zero. Under a Monday-Friday schedule, Friday October 16, 2026 plus one business day is Monday October 19. If that Monday is excluded, the result becomes Tuesday October 20.

Consequential deadlines

Legal, tax, bank, shipping, trading, and contractual calendars can define business days differently. Verify the governing rules instead of treating a generic calculator as authoritative.