While the file enclosed by Roopanagaraju is one way of calculating age, you can also try the following:
AGE Calculation in Excel
Years: =DATEDIF(B3, TODAY(), "y") wherein in Cell B3 you may enter the date of birth.
Months: =DATEDIF(B3, TODAY(), "ym") wherein in Cell B3 you may enter the date of birth.
Days: =DATEDIF(B3, TODAY(), "md") wherein in Cell B3 you may enter the date of birth.
The above-mentioned formulas will give you the exact number of years, months, and days lived to date. You may write back to me at [Email Removed For Privacy Reasons] for any further clarifications.
Regards,
JSR