Add Business Days to a DateFree online date & time calculator — instant results, no sign-up

R = S + k* calendar days, where k* = min{k ∈ ℤ≥0 : Σ(i=1 to k) b(S + i calendar days) = N}; b(d) = 1 if d is Monday–Friday and 0 otherwise. For S = 2026-10-23 and N = 10, k* = 14, so R = 2026-11-06.

• SThe start date, 2026-10-23 in the worked example.
• NThe whole number of business days to add, 10 in the worked example.
• dA calendar date being tested to determine whether it is a weekday.
• b(d)A counting function that returns 1 for Monday through Friday and 0 for Saturday or Sunday, without checking holidays.
• iThe calendar-day offset after the start date used in the sum.
• kA candidate nonnegative whole number of calendar days to advance.
• k*The smallest calendar-day offset that accumulates exactly N business days; it is 14 in the worked example.
• RThe resulting date after adding the requested business days.

Begin with the start date and a business-day count of zero. Advance one calendar day at a time, increasing the count only when the new date is Monday through Friday, and stop when the count reaches the requested total. The start date itself is not counted. From Friday, October 23, 2026, skip October 24–25, count October 26–30 as business days 1–5, skip October 31 and November 1, then count November 2–6 as business days 6–10.

These are the calculator's starting values and the results it actually produces for them.

1. 1Enter the Start date; for the worked example, keep 2026-10-23.
2. 2Enter the Business days to add; for the worked example, keep 10.
3. 3Run the calculation to count weekdays after the start date while skipping Saturdays and Sundays.
4. 4Read the resulting date as Fri, November 6, 2026, and use 2026-11-06 when an ISO-formatted date is needed.
5. 5Review the note, “Weekends skipped; holidays not excluded,” before using the date for a deadline.