Excel formula to generate a date + a certain number of years

You can "add" a number of days using a formula in Excel to calculate a date plus x number of years.

The syntax works like this:

Put the date in Cell A1

In Cell B1, put in a formula that says =A1+(365.25*20) and then format the result as a date (Format menu, format cells, click date and MM/DD/YY)

The attached spreadsheet has the formulas for 20, 25, and 30 years, as well as a Years to date which uses the "today" function to subtract the current date from the date in A1, and then calculates it into years. 

You need to do 365.25 to account for Leap years (although the date creeping back by 10 days over the course of 40 years probably doesn't matter)