Try:
DateDiff("yyyy", [DateofBirth], Date())
If you actually want the person's age calculated correctly (regardless
whether they have had a birthday this year or not), see:
http://allenbrowne.com/func-08.html

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Allen Browne - Microsoft MVP. Perth, Western Australia
Tips for Access users - http://allenbrowne.com/tips.html
Reply to group, rather than allenbrowne at mvps dot org.