A standard letterhead size outside of North America is the A4 size (210mm x 297mm). Within North America, though, standard letterheads are printed at 8.5” x 11”. The letterhead design (or branding area) often occupies one or more of the following spaces: the header, footer, or left sidebar. There may also be other elements of the design surrounding the text. There is not a set standard for branding area size, but you should always ensure that the content of your letter can be easily read and that the letterhead design doesn’t detract from it.