Nth Weekday of Month Calculator

Worked example

The third Monday of January 2027 is January 18. January 1, 2027 is a Friday, so the first Monday is January 4, and each subsequent Monday falls 7 days later, making the third Monday January 4 plus 14 days, which is January 18. February 2027 has only 28 days, so it contains exactly 4 of each weekday and has no 5th occurrence of any of them that year.

When the 5th occurrence doesn't exist

Not every month has a 5th occurrence of every weekday. A month needs at least 29 days containing that weekday for a 5th one to exist, which only happens for some weekdays in a 29-, 30-, or 31-day month. The calculator states plainly when the requested occurrence doesn't exist rather than returning a date from the wrong month.

Common mistakes

• Assuming a "5th Friday" recurrence happens every month. It only exists in months with 29 or more days that also happen to start on the right weekday, so it is genuinely absent more often than it appears.
• Miscounting by treating "the third Monday" as always 21 days after the 1st of the month. It is 14 days after the first occurrence of that weekday, not after the 1st of the month, and those two reference points only coincide when the month happens to start on that weekday.

Limitations

This is calendar arithmetic only. It does not determine whether a specific recurring event actually happens on this pattern, so a meeting or payment described as "the third Monday" should be confirmed against its own source before this date is treated as final.