How do I add date or day counter?

[UAEPrivate]

Infopath 2003
After inserting a future date using a day picker, I am trying to have a day
countdown in a field that shows me how many days left until that future date.

 

[S.Y.M. Wong-A-Ton]

You'll have to write code for this one. Try this article:
http://enterprise-solutions.swits.net/infopath/datediff-vbscript-infopath.htm