title_body: Scaling all pages in a PDF or DJVU file to the same size
upvoted_answer: There is a program called jPdftweak which will let you scale pdf pages to whatever size you would want. You can set the parameters for the conversion to the larger page size and jPdftweak will scale all the pages in the file in accordance with the settings you have made. jPdftweak is a cross-platform, free Java program.