Image size calculator/converter.

This should be something easy to do for the right person. I just don't have time to figure it out.

I sell custom decals and all my sizing is based of the width the customer orders. But a lot of customers need to know what height a decal will be at a certain width. Or want to know what size they need to order based off the height they want. I figure the easiest way to do this would be to use the image since (for most products) for script reference since it will give you precisely the right size ratio.

Customer should be able to put in height or width and it tells what the other size works out to be. Maybe a little box under the image that says something along the lines of “input width or height for proportional sizing”. This doesn't have to be integrating into the size option but that would be awesome if it could. Open to suggestions on how to approach this or what you feel would work best. Here is an example of something similar to what I am wanting: - This website is for sale! - ultimatedecals Resources and Information.

Did anyone get this sorted, I am looking for something like this one here at the top right of the page.