Koha System

What Is a MARC Record? A Practical Guide for Koha Migrations

A practical explanation of MARC records for libraries preparing to migrate to Koha.

May 12, 2026 3 min read

A MARC record is a structured catalogue record used by libraries to describe books, journals, media, and other resources. MARC stands for Machine-Readable Cataloging.

If you are migrating to Koha, MARC matters because Koha uses MARC records to store and display bibliographic information.

Why MARC matters in a Koha migration

During a migration, your existing catalogue data needs to become usable in Koha. That usually means preparing records in a MARC format such as MARC21 binary (.mrc) or MARCXML (.marcxml).

If your current system cannot export MARC, your data may need to be mapped from a spreadsheet, CSV file, database export, or another structure into MARC fields.

What a MARC record contains

A MARC bibliographic record may include: Title, Author, ISBN, Publisher, Publication date, Edition, Subjects, Notes, Physical description, Language, Classification or call number, and local item information depending on system and migration method.

In Koha, bibliographic data describes the title, while item data describes the individual copy or holding.

Fields, indicators, and subfields

MARC records are divided into fields.

Field	Common meaning
020	ISBN
100	Main personal author
245	Title statement
250	Edition statement
264 or 260	Publication information
300	Physical description
500	General note
650	Subject heading
952	Common Koha item field, depending on configuration

Many fields include indicators and subfields. For example: 245 10 $a Introduction to library systems / $c Jane Smith. — where 245 is the title field, 1 and 0 are indicators, $a contains the title, and $c contains the statement of responsibility.

Fixed fields

Some MARC fields are fixed-length fields whose meaning depends on character position. Important examples include the Leader and 008. These fields may affect material type, language, dates, indexing, and display. MARCReady can help flag incomplete or malformed fixed fields for review.

MARC vs item data

A common migration issue is confusing bibliographic records with item records.

Bibliographic record describes the title: Author, Title, Publisher, ISBN, Edition, Subjects.

Item record describes a copy owned by the library: Barcode, Branch, Shelving location, Item type, Call number, Status.

A book with three physical copies may have one bibliographic record and three item records.

What if your library does not have MARC records?

Some small libraries have catalogue data in spreadsheets or simple databases instead of MARC. That does not necessarily prevent migration to Koha. However, the data needs to be mapped into a structure Koha can import.

MARCReady can help by suggesting MARC mappings from spreadsheet columns such as Title, Author, ISBN, Publisher, Publication year, Subject, Call number, and Barcode.

What MARCReady can help with

MARCReady can help libraries: review MARC21 files, review MARCXML files, convert structured spreadsheets into MARC-style records, identify common MARC problems, prepare records for Koha import, and preview suggested changes before export.

What still needs human review

Librarians should still review: subject headings, call numbers, local notes, item mappings, duplicate records, local fields, and authority control needs.