In Excel, I set my page to fit to size, but when I preview it, it does not go all the way to the edges of my?

margins, even though the margins are within printable range, and the "Adjust to %age of normal size is filling in at less than 100%". It seems almost as if I put extra rows and columns in my print range, even though i didn't. How can I get the doent to take up more of the page and less blank border around it?