Is there a function in excel to automatically calculate age using date of birth

Question

What Excel function uses information from the date of the birth column to calculate age in the age column?

The date of birth is entered in Column D of a table for customers, and the age is entered in Column H; How can I utilize the Date of Birth in Column D and a function or formula in Excel to automatically determine Age in Column H?

Answer 1

Try 

=INT((YEARFRAC(TODAY(),B3,1)))

 Where cell B3 contains a date like 01/01/1970 will return age in years.