Layout Based Visit Forms to count days/weeks between 2 dates

I am using OpenEMR version 4.2 (xampp) on a windows machine.

I know how to create LBV Forms, have created a few that works.

I want to know if I can create LBVF to calculate weeks and days from a date the user picks on the form (or use default current date) to a future or current date on the same LBV form.

I don’t have coding skills, I can only use admin privileges to customize stuff among a few others.

I have been enjoying so much support from this great community.

Help will be much appreciated.

Thanks.