I was able to calculate working days excluding weekends and USA Holidays following this blog https://alecpojidaev.wordpress.com/2008/12/30/infopath-codeless-programming-walkthrough-2/ and creating an XML data that holds all the USA Federal holidays in a year and query the xml files with a secondary data connection.(Thanks to ALEC POJIDAEV'S, it's very useful). I want to set a due date in infopath form by adding 8 working days ( excluding weekends and USA Federal Holidays). The default start date can be set as today's date. Please take a look at the following sample workday calculation posted at https://onedrive.live.com/?cid=E5A123FCA40349AD&group=0&id=E5A123FCA40349AD%21626&parId=E5A123FCA40349AD%21149&o=OneUp The infopath form is a browser enabled that will be published in sharepoint 2013 please share your thoughts?