How this calculator works
One hundred eighty days is about half a year, a common waiting period and a frequent policy window. It is not exactly six calendar months: six months run 181 to 184 days in a common year, depending on which months are included, and a leap day can add one more. The calculator moves by 180 whole calendar days, so the answer is stable and independent of month names. The weekdays-inside figure counts Monday to Friday dates inside the span and is a planning estimate, not a business-day deadline calculation.
Formula
result = fromOrdinal(O(start date) + 180) forward, or fromOrdinal(O(start date) - 180) backward. The span is 25 weeks and 5 days. Weekdays inside counts Monday to Friday dates in the half-open interval between the two dates.
Worked example
180 days after 2026-11-01 is 2027-04-30, a Friday, 25 weeks and 5 days later with 130 weekdays inside. 180 days before 2026-11-01 is 2026-05-05, a Tuesday.
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Frequently asked questions
Is 180 days half a year?
Close but not exact. Half of a common year is 182.5 days, so 180 days falls two or three days short. In a leap year, half is 183 days. Use the 6 month calculator when the question is about calendar months.
What is a 180-day rule?
The phrase appears in several unrelated contexts, including tax residence, immigration presence and insurance waiting periods. Each has its own counting rule, so treat the date from this page as a starting point and confirm the definition in the governing document.
Does the result include both the first and last date?
No. The count is the number of calendar-day boundaries crossed, so the two dates are not both counted. If a rule counts both endpoints, add one day to the result.