Hi!
I read your description well and understood your requirements.
actually, wordpress is a content management system, so for this task, i don't think you need such a big script to install on your server...
this can be done using simple javascript, and Javascript is client-side which runs on clients machine...
once the user visit this page and view the system, script will work fine.
if you have the calculation, this would be much more easier.
Also, i can create a responsive page design which will automatically resize according to the users browser width.
Regards,
Ruchira Jayasuriya