Say you need to create the following calculated column in different sites that have different regional settings: English, French, etc. to format the DateTime [Start Time] filed to "dd-mm-yyyy". The following formula would look list this in English - with a comma separator: = TEXT ([ Start Time ] , "dd-mm-yyyy" ) Like this in french - with a semicolon separator: = TEXT ([ Start Time ] ; "dd-mm-yyyy" ) When creating the column from from code behind to treat this the SP Web . Locale . TextInfo . ListSeparator property must be used to get the correct list separator: SPList spList = SPContext . Current . Web . Lists [ "List Title" ]; string newFieldName = spList . Add ( "CalculatedField" , SPFieldType . Calculated , false ); SPFieldCalculated newField = ( SPFieldCalculated ) spList . GetField ( newFieldName ); newField . Formula = String . Format (@ "=TEXT([Start Time]{0} ""dd-mm-yyyy"")...