Page numbers

Page numbers are not only essential for books. They may also be used for e-books, calendars, sheet music and other product forms, in order to provide the customer with a rapid and clear picture of the scope of the product.

Page number information is provided in an extent composite. It is possible to provide multiple types of page numbers for a product. The type of page number is listed in ExtentType or b218 using values from code list 23. The following entries are possible in Metabooks. When supplying types of page numbers, please note carefully whether your product is a digital or printed one.

Specification for non-digital products (e.g. print products)

Code Type Explanation
11 Total number of pages
  • leading specification
Sum of all pages with Roman and Arabic numerals as well as unnumbered filled pages.
  • Number of pages main content (00), front matter (03), trailer (04) and unnumbered pages (12), or
  • Total of the number of numbered pages (05) and unnumbered pages (12)
00 Page number main content Highest-numbered page with Arabic numerals in a book or, for a book without foliation, or (rarely) with several numbered sequences of content, the total number of pages containing the main content of the book This may include numbered, but also empty pages (e. g. pages to ensure a chapter starts on the recto of a page), and need not contain unnumbered (but containing content) pages such as inserts. The trailer (e. g. index) should not be included, even if the numbering continues there.
03 Number of pages front matter
  • Arabic or Roman numerals possible
The total number of pages (usually numbered with Roman numerals) preceding the main content of the book (so-called front matter) The front matter normally includes various title and masthead pages, table of contents, introduction, preface, etc.
04 Number of pages trailer
  • Arabic or Roman numerals possible
The total number of pages (usually numbered with Roman numerals) following the main content of the book (so-called trailer) The trailer usually contains the postscript, annexes, final notes, indices, etc. Empty or advertising pages included solely for printing and binding purposes are not part of it.
05 Total number of pages The sum total of all pages with Roman and Arabic numerals including numbered empty pages, but excluding unnumbered (filled) pages.
  • Number of pages main content (00), front matter (03), trailer (05).
06 Number of pages produced The number of all pages in a book, including unnumbered pages, front matter, trailer, etc. This includes empty pages filled only for printing and binding purposes.
12 Total unnumbered pages The sum of all unnumbered pages with content, which are part of the main content, such as inserts with unnumbered pages.

ONIX recommendation: For most books, the preferred number of pages is either the page number for the main content (00) or the Total number of pages (11) Books with substantial front matter or trailer should include the pages of the front matter, the trailer or the number of numbered pages as well. Books with inserts should include the number of pages for those as well.

Specification for digital products

Code Type of number Explanation
07 Precise number of pages The sum of all pages, including the cover as page 1. This number is only used for digital publications with precise pagination.
08 Number of pages of the included print product The sum of all pages of the respective print product, if the digital product does not have precise pagination.
10 Estimated number of pages An estimate of the number of pages of a digital product that has neither precise pagination nor an equivalent print product. Only to be used for exclusively digital products.

Note: if you enter page numbers of non-digital products for your digital ones (and vice versa), Metabooks will accept these and forward them to the booksellers.

In ExtentUnit or b220 , the value 03 allows you to define the unit as a number of pages.

In ONIX 3.0, you can enter within one extent composite values for Arabic numerals (ExtentValue or_b219_) and Roman numerals (ExtentValueRoman or x421 ).

Please note: Metabooks accepts only Roman numerals for front matter and trailer. If you do enter an Arabic numeral, Metabooks will export this also as a Roman numeral (in ONIX 3.0 for front matter and trailer in the same extent composite). For all other types of page numbers, Arabic numerals are accepted and forwarded exclusively.

An entry for a front matter section containing 10 pages looks as follows

ONIX 3.0 Short
<extent>
  <b218>03</b218>
  <x421>X</x421>
  <b220>03</b220>
</extent>
ONIX 3.0 Reference
<Extent>
  <ExtentType>03</ExtentType>
  <ExtentValueRoman>X</ExtentValueRoman>
  <ExtentUnit>03</ExtentUnit>
</Extent>