Contents   Fixed field   0xx   1xx   2xx   3xx   4xx   5xx   6xx   7xx   8xx   9xx

About This Guide



Bibliographic Formats and Standards is a guide to machine-readable cataloging records in WorldCat. It provides tagging conventions, input standards and guidelines for entering information into WorldCat.


Bibliographic Formats and Standards assumes you are familiar with Anglo-American Cataloguing Rules, second edition, 2004 Revision, and other standard cataloging reference material. Some sections also assume you have a general knowledge of data processing and databases.

Superseded documents

This edition supersedes the cataloging information in these technical bulletins:

  • TB256         Abbreviated-Level Record Guidelines
  • TB255         OCLC-MARC Format Update 2008
  • TB254         OCLC-MARC Format Update 2007 and Institution Records to Accommodate the RLG Union Catalog
  • TB253         ISBN and OCLC Number Changes
  • TB252         OCLC-MARC Format Update 2006
  • TB250         Parallel Records
  • TB249         OCLC-MARC Format Update 2003
  • TB247         OCLC-MARC Format Update 2002
  • TB246         Database Enrichment


The examples provided are illustrative, not prescriptive. Do not take the examples or the form in which they are presented as instructions. Because of the dynamic nature of WorldCat, some examples may not appear online now as shown in the document.

Additional examples

When you find a record that illustrates a cataloging rule or coding practice particularly well, please share it with us. Please send an e-mail message giving the OCLC record number and comments to

Input Standards


OCLC has established input standards based on the Library of Congress National Level Full & Minimal Requirements ( Previously, OCLC revised some of the NLR standards on the advice of OCLC advisory groups. At the field level:

  • Level I represents full or complete cataloging.
  • Level K represents minimal-level cataloging.

Standards for indicators and subfields are in effect only when the field itself is applicable.

Input Standards table

A table identifies level I and level K input standards at the beginning of the fixed-field elements section and at the beginning of each variable field description. The level I standard is given first, followed by a slash ( / ), then the level K standard. Core-level standards are not identified.

These abbreviations are used in the fixed-field element Input Standards table:

SS (System-supplied) System-generated data that you cannot change.
M (Mandatory) Data you must enter to meet the designated standard.
R (Required if applicable or readily available) Data is applicable if:
  1. AACR2 instructs you to enter the data when it applies
  2. It is necessary to justify the existence of an added entry (AACR2 rule 21.29)
  3. It is essential for efficient access to, or effective processing of, records
Data is readily available from:
  • The item in hand
  • Other bibliographic records
  • OCLC Authority file records
O (Optional) Data you decide whether to enter.

Note: The following characters appear in the Input Standards tables:

blank character Blank space, distinguished from a fill character, used when a blank is significant.
fill character A fill character, distinguished from a blank space.

The following is an example of the Input Standards table at the beginning of each variable field description.

653 Index Term-Uncontrolled (R)___________________
Input Standards
1st Indicator Level of subject. The level of the subject entry. Use the 1st indicator to distinguish primary and secondary descriptors.
blank character No information provided. No information as to the level of the subject term is provided.
0 No level specified. The level of the subject term could be determined, but is not specified.
1 Primary. A subject covers the main focus or subject content of the material.
2nd Indicator Undefined. The 2nd indicator position is undefined and contains a blank ( blank character ).
blank character Undefined
Subfields (R=Repeatable NR=Nonrepeatable) Input Standard
‡a Uncontrolled term (R) Mandatory/Mandatory


(R) identifies a field or subfield as repeatable, which means it may occur more than once.

  • A repeatable field may occur more than once in a record.
  • A repeatable subfield may occur more than once in a field.

(NR) identifies the field or subfield as nonrepeatable. Fields or subfields are nonrepeatable for a variety of reasons:

  • The data element may occur no more than once for a given item.
  • The data element may occur more than once, but you enter multiple data elements in the same subfield.
  • The data element may occur more than once, but you enter multiple data elements in separate fields.


Some fields, subfields, elements or values may be marked Obsolete. Do not use . Although some records in WorldCat may still contain this coding, do not use these fields, subfields, elements or values in current cataloging.

Additionally, some fields, subfields, elements or values have been completely removed from the online system. They are considered as invalid. Descriptive information has been removed from this document.



OCLC acknowledges the efforts of all the people who participated in producing Bibliographic Formats and Standards.

OCLC reviewers

Brenda Block, Robert Bremer, Robin Buser, Ellen Caplan, Virginia Dudley, Linda Gabel, Ed Glazier, Luanne Goodson, Chris Grabenstatter, Richard Greene, Shanna Griffith, Mary Haessig, Peter Insabella, Hisako Kotaka, Glenn Patton, Laura Ramsey, Robin Six, Anna Sylvester, Patty Thomas, Susan Walker, Susan Westberg, David Whitehair, Cynthia Whitacre, Julie Whitley, and David Van Dyk

Network reviewers

Amy Benson (NELINET), Marlee Dorn Givens (SOLINET), Linda Gonzales (BCR), Susan Lewis (MLNC); and Roman Panchyshyn (OHIONET)


OCLC acknowledges Nancy B. Olson for permission to use her chart from A Catalogers Guide to MARC Coding and Tagging for Audiovisual Material. DeKalb, Ill.: Minnesota Scholarly Press, 1993.

OCLC acknowledges Amigos Library Services for permission to use charts from Amigos Technical Memorandum T79-37, Formatting of Call Numbers.

OCLC acknowledges the Public Library of Cincinnati and Hamilton County for permission to use its chart Summary of Field 260 ‡c .

Special thanks to Linda Gabel for the Summary of Leader and 008 Field Bytes and Summary of 008 and 006 Field Bytes.

Special thanks to Anthony F. Chirakos and Ron Jones for their work on the previous editions.


Chris Dawson


Peter Insabella

Subject matter expert

Jay Weitz

Production and technical development

Lorna Williamson and Mike Limes