Business Days Calculator

Method (Count mode): the two input dates are sorted so the earlier one is treated as the start. The calculator then walks the calendar one day at a time from start to end, inclusive, checking the day of the week on each step — Sunday and Saturday are excluded, so any other day is counted as a business day. This day-by-day loop is simple and fully accurate for date ranges up to several years; it is not optimised for huge spans, but that is not a practical concern for typical business-day questions. Method (Add mode): starting from the input date, the calculator steps forward one calendar day at a time (or backward, if the number entered is negative), and only decrements the remaining count when the day landed on is a weekday. This naturally skips weekends: if adding 1 business day to a Friday, the loop steps to Saturday (not a weekday, do not decrement), then Sunday (not a weekday, do not decrement), then Monday (a weekday — decrement, remaining reaches 0, stop). Result: Friday + 1 business day = the following Monday. Worked example 1 (Count mode): start = Monday 6 July 2026, end = Friday 17 July 2026. That is a full two-week span (14 calendar days) containing 10 weekdays and 4 weekend days. Result: 10 business days. Worked example 2 (Add mode): start = Wednesday 15 July 2026, add 5 business days. Thu 16, Fri 17 (2 so far), Sat/Sun skipped, Mon 20, Tue 21, Wed 22 (5 total). Result: Wednesday 22 July 2026. Edge cases handled: - Start and end date entered in reverse order (end before start): the calculator swaps them internally before counting, so the result is always a positive count regardless of input order. - Adding a negative number of business days: the loop simply steps backward through the calendar instead of forward, correctly skipping weekends in the reverse direction too — useful for working out "what date did we need to start by, to finish in N business days." - Adding zero business days: returns the start date unchanged. - Start date falling on a weekend (Add mode): the loop always begins stepping from the day after the start date, so the starting weekend day is never miscounted as day one. Practical tip: because public holidays are not excluded (see "About" above), when working with a formal deadline that must account for holidays, first identify how many holidays fall inside your business-day range from the relevant public holiday calendar, then either add that many extra business days to your target count, or manually adjust the resulting date forward past each holiday. For most short ranges (under a month) in a given country, there are rarely more than one or two holidays to account for.