I am assuming that 1/8/2010 is the last day of some pay period, because if the next pay period after today starts on 10/29/2011 (per your formula), a pay period started on 1/9/2010. I am also assuming that a pay period is 14 days.
You haven't defined what you mean by the last pay period of the year. This gives you the last pay period that ends in the current year:
=(MOD(DATE(2010,1,8)-DATE(YEAR(TODAY()),12,5),14)+DATE(YEAR(TODAY()),12,5))+1
This gives you the last pay period that starts in the current year:
=(MOD(DATE(2010,1,8)-DATE(YEAR(TODAY()),12,17),14)+DATE(YEAR(TODAY()),12,17))+1
Bookmarks