Question about excel and HTML5

Hey everyone this is my first time post here and I have a question about excel and html coding...

So at my company we are using Sharepoint 2010 and they have somehow built their website through this software. From my understanding and from what they told me, it has very basic html coding that can be edited through "webparts" placed around pages. They also gave me this excel document that determines a screen size in feet and in mm from what the customer puts in. So for example I would say I need a 10ft H X 22ft W video screen and what pops out is what the actual size we can do for them which is 10.12ft H X 22.00 W or 3.086mm H X 6.706 W. These obv change by what the customer puts in each time.

So they basically want me to make a "calculator" that can do the same thing as whatever that excel document is doing and have it displayed on the webpage using code or some other method.

I'm an intern graphic designer so I do know basic HTML, CSS, Javascript and so on but I am definitely not a web developer just yet.

So is there any way I could this in HTML? Is there an application or a tutorial I could look at as well that could help in the process. I also tried embedding the excel document into the page but It wasnt editable so no one could type any values in. If there is a way to make the editable I'm down for that Idea as well.

Let me know If you guys need more information