Adding a calendar month is not adding 30 days
Understand month-end clamping and keep calendar arithmetic separate from business-day rules.
Method
A calendar month moves the month number while retaining the day when possible. If that day does not exist in the destination month, this calculator clamps to its last day. Adding 30 days instead advances exactly 30 calendar days. Both operations can be reasonable, but they express different instructions.
Worked example
From 31 January 2026, adding one calendar month gives 28 February. Adding 30 calendar days gives 2 March. From 31 January 2024, the one-month result is 29 February because that year is a leap year. Check the chosen direction and the operation order when months and days are combined.
What to check
Do not call a clamped monthly date a fixed number of days. Recurring schedules may need to preserve an original end-of-month rule rather than repeatedly using the prior clamped date. Workday exclusions require the business-days tool; this date-add calculation does not skip holidays.