Guide To Book Sizes & Formats.

Terminology and Definitions

If you are new to the world of Book Collecting, especially with respect to Antiquarian and Vintage Books there are many terms and definitions that you might find confusing. On this page we are exploring the expressions and abbreviations used to describe the shape and dimensions of an actual physical book.

The origin of these confusing sounding terms is actually quite simple. When books were first created they were made from multiple large sheets of paper upon which the text, print and illustration was created. 

The large sheets of paper were then folded multiple times, the more times they were folded the smaller the pages created hence the descriptions.

For example, the term ‘Folio’ is used when the original sheet of paper was folded only once, creating two pages or leaves. A 'Quarto' book has the larger sheets folded twice each creating four distinct quarters. 

In Antiquarian books there were many differences in size due to the approximations and variations in production of paper. 

Modern day printers are not constrained by the same restrictions of format so nowadays there is a much greater variation and many modern books do not strictly adhere to traditional printing formats. 

Also traditionally when describing the size of a book only the size of the leaves or pages are measured to give the dimensions. 

Nowadays we find this can be confusing for customers so may provide both the traditional terminology (where applicable) along with the actual gross measurements including the extremities of the book to the tip of its cover/boards.

Traditional Paperbacks books are much simpler as the cardboard covers rarely extend beyond the actual size of the pages. Softcovers of books occasionally extend beyond the size of the pages in both Modern and Vintage formats.

The field of miniature book collecting has evolved over the years changing what is deemed to be a true miniature. Nowadays generally a book that is less than 3" inches at the greatest dimension is classed as a miniature. Some of the tiny 18th century miniature books were actually as small as an inch in size.  Wikipedia has an excellent page about Miniature Books.

Some dealers describe any book under 4" inches in size as a miniature but many see this as a loose description as these books would actually most probably align more closely with a Quadragesimo-Octavo (48mo) sized book.

Below is a helpful table illustrating the terms, abbreviations and sizes for your convenience: