Need to know what 1 inch is equal to for cell width.

[phoenixtalonv3]

Alright I've been all over the internet and I'm not a expert with excel but I'm not new at it. Just tell me strait forward no 1/72 stuff what, in point value, is 1 inch = in excel cell width?

Because I'm trying to help my father setup and easy template for him to make business cards. I just wanna set it for the card size for 10 cards per page at 3.5 inches width and 2 inches height.

[phoenixtalonv3]

Another question I had I guess too was. When I make this page I need to configure the margins and everything to that of the business card paper?