there. If I create a page and then want to duplicate it

Hi there. If I create a page and then want to duplicate it with exactly the same elements, same size etc, how can I do that? I know I can clone a box, but only on the same page. How do I create a page template so that my client can recreate the same layout for another page?
As it is now, it looks like once I create a page it only exists in the front end, and there is no way of knowing exactly how to duplicate the same layout on a different page.