Paper and Book Sizes The size of a book’s pages is based on the size of the sheets of paper it is printed on and the number of pages printed per sheet. For example: for quarto, 4 pages are printed on a sheet of paper 19” by 24”. American and English measurements differed from each other. Modern figures from American Library Association These figures come from http://www.trussel.com/books/booksize.htm. I’ve emailed the ALA directly because their webpage is not available due to their updating the site. Quarto – 9 ½”x 12” 24mo. (vincesimo-quarto) Royal Octavo – 7” x 11” 32mo. (Trigesimo-segundo) – 3 ½” x 5 ½” Octavo – 6”x 9” 48mo. (Quadrasedisimo-octavo) – 2 ½” x 4” Duodecimo (12mo) – 5” x 7 3/8” 64mo. (Sexagesimo-quarto) – 2” x 3” Octodecimo (18mo.)– 4” x 6 ½” American Book Sizes (based on The International Directory of Booksellers and Bibliophile’s Manual, Including Lists of The Public Libraries of the World, edited by James Clegg (London: Elliot Stock; New York: Dodd, Mead, & Co., 1899), Clegg's International Directory of the World's Book, (1894) and some math using Royal, Medium and Imperial printer size papers.) From Medium paper 24” x 19” From Royal paper 25” x 20” Medium Folio 19” x 12” Royal folio 20”x12 ½” Medium Quarto 9 ½”x 12” Royal Quarto 10” x 12 ½” Medium Octavo 6”x 9” Royal Octavo 10” x 6 ¼” Medium Duodecimo (12mo) 5” x 7 3/8” Royal Sextodecim (16mo) 5" x 6 ¼” Medium Sextodecim (16mo) 6” x 4 ½” Medium Octodecimo (18mo.) 4” x 6 ½” From Imperial paper 30” x22” Medium 24mo. (vincesimo-quarto) Imperial Folio – 22” x 15” Medium 32mo. (Trigesimo-segundo) 3 ½” x 5 ½” Imperial Quarto – 11” x 15” Medium 48mo. (Quadrasedisimo-octavo) 2 ½” x 4” Imperial Octavos – 11” x 7 ½” 64mo. (Sexagesimo-quarto) – 2” x 3” American Writing Paper Sizes (based on The International Directory of Booksellers and Bibliophile’s Manual, Including Lists of The Public Libraries of the World, edited by James Clegg (London: Elliot Stock; New York: Dodd, Mead, & Co., 1899), Clegg's International Directory of the World's Book, (1894) and some math using Royal, Medium and Imperial printer size papers.) Empire 72”x48” Super Royal 27”x19 Pott 15”x12 ½” Antiquarian 53”x31” Royal 24”x19” Sheet & Half Post 22 ½”x12 ½” Double Elephant 40”x26 ¾” Demy 20”x15 ½” Sheet & Third Cap 22”x13 ½” Atlas 33”x26” Large Post 21”x16 ½” Sheet & Half Cap 24 ½”x13 ½” Columbier 34 ½”x23 ½” Copy 20”x16” Double Foolscap 26 ½”x16 ¾” Imperial 34”x22” Post 19”x15 ¼” Elephant 28”x23” Foolscap 17”x13 ½” .