The easiest solution to my problem would be to locate an Excel spreadsheet for Federal Government Retirement calculations (FERS) but I can’t seem to find one.

Barring that, I need help with calculations on my retirement worksheet. First, I need the formula to correctly calculate my adjusted retirement service start date subtracting out Government time which counted for on-the job benefits but not retirement benefits. I’ve already calculated the time for each individual non-credit time period involved (years, months, days format). I now need to take these non-credit time period totals and subtract them from my original Service start date (M/DD/YY format) and come up with an a new, adjusted service start date (in MM/DD/YY format). I would also like right formula to use to calculate an accurate retirement eligibility date. I am having trouble with accuracy (related to the 30 day months used by Excel in its calculations). Any suggestions would be appreciated.