generating year of birth based on date and age

so, let's say you have the age in cell A2 (like 22) and today() in cell B2, this would generate a "rough" DOB =B2-A2

so for year, if you type in 2016 into cell B2 or this in to B2 =YEAR(TODAY()) then use the same subtraction as post #2 =B2-A2 then format as a number you will have the year of birth. Just so you understand, it will not be completely accurate unless your ages are very accurate.
So in my first example, the age of 22 and the year of 2016 will get you 1994 as the year of birth. If you have 22.216 as the age you get 1994 as year, if you have 22.618 as the age you get 1993. So accuracy will be dependent on the accuracy of the age.

how would excel identify age (22) as a year and not a number?

I'm not sure I understand your question. Did you try the recommendation in post #4?
Uploading a sample spreadsheet could help get you a better answer.

Try this:

Please Login or Register  to view this content.

If you're wanting to generate representative Dates of Birth, I'd suggest using 30th June or 1st July instead of 1st January - that way there's a 50/50 chance (approximately) that the DoB is at least in the right year. That would make popipipo's formula into this:

Formula:

Please Login or Register  to view this content.