Sizes for Books

The terms in use for describing book formats are derived from printing methodology and the size of sheets of paper, which of course is handmade.
When two leaves (four pages when printed on both sides) were printed on a sheet so that it could be folded once, collated with other folded sheets and bound, the format of the volume was a "folio". When four leaves (eight pages) were printed on the same size sheet, which would later be folded twice, the format of the resultant volume was a "quarto" (four leaves). The term "octavo" relates to the sheet having eight leaves printed on it.

Real life booksellers are often providing the height of a book in inches or centimetres rather than using these early terms which do not relate directly to the sheet size or process used for printing today. The following is offered as a guide to convert book formats to approximate book sizes:

• Folio: more than 13 inches tall;
• Quarto (4to): approx. 10 to 13 inches tall, average 12 inches;
• Octavo (8vo): approx. 8 to 10 inches tall, average 9 inches;
• Duodecimo (12mo): approx. 7 to 8 inches tall, average 7.5 inches;
• Sextodecimo (16mo): approx. 6 to 7 inches tall, average 6.5 inches.

There are smaller and larger books, i.e. many miniatures are 64mo, and most hardbound books are either octavo or duodecimo in size.

Related Organizations

• Guild of Bookbinders
• Guild of Papermakers
• Printer's Guild