How To Extract Day, Month, or Year From A Date/DatePicker In InfoPath Forms For SharePoint

In InfoPath, under Fields, Right Click on the single line of text field and choose Field Properties.

Under the Default Value section click the “fx” button beside the blank field.

To extract the day number of a date, use

number(substring([Date Picker Field], 9, 2))

To extract the month number of a date, use

number(substring([Date Picker Field], 6, 2))

To extract the year number of a date, use

number(substring([Date Picker Field], 1, 4))

Where [Date Picker Field] represents a date picker control or the function of today() to pull any of those from today’s date.