Welcome!
I would recommend creating a User Defined Function. You can pass in the user name as one of the variables, and have it calculate differently for them.
See here for User Defined Functions: http://www.fontstuff.com/vba/vbatut04.htm
I would probably use Case statements for each different user/calculation (http://www.techonthenet.com/access/f...anced/case.php), i.e.
Code:
Select Case UserName
Case "John"
' Do John's calculation here
Case "Mary"
' Do Mary's calculation here
...
Case Else
....
End Select