Don posted another of his excellent tutorials recently, "Calculate Someone's Age in Excel".
It said you can use the formula "=YEAR(TODAY())- YEAR(<<cell reference>>)" when you know their date of birth and have that stored in <<cell reference>>)".
I think that tells you how old they'll be this year (after their birthday) really.
To see how old they are today, and have their date of birth in cell A5, you can use:
=AND(MONTH(TODAY())>=MONTH(A5),DAY(TODAY())>=DAY(A5)) + YEAR(TODAY())-YEAR(A5)-1
(which avoids IF functions by using AND and minus 1).
Is there a better, less verbose, to get their exact age in years?
### CORRECTION:
See the less verbose formula proposed by Variatus, seems to work well- thanks Variatus (Don, I could not "Select" his answer not add to the discussions started by him/her or you for some reason so have put my comments in here).
The formula I suggested above doesn't work properly (sorry). The logic is flawed and should need to be the overly-long:
=OR(MONTH(TODAY())>MONTH(A5), AND(MONTH(TODAY())=MONTH(A5),DAY(TODAY())>=DAY(A5)))+YEAR(TODAY())-YEAR(A5)-1
or if like Variatus you have A1 with formula =TODAY() :
=OR(MONTH($A$1)>MONTH(A5), AND(MONTH($A$1)=MONTH(A5),DAY($A$1)>=DAY(A5)))+YEAR($A$1)-YEAR(A5)-1
Better to use the formula from Variatus!