Koha System

MARCReady — Supported Input and Output Formats

Supported input and output formats for MARCReady catalogue preparation and MARC repair.

May 12, 2026 3 min read

MARCReady accepts catalogue data in several common formats and exports records in standard MARC formats used by Koha. This page lists supported input and output formats and explains when each format is useful.

See the MARCReady overview for a general introduction to the tool.

Supported input formats

Format	Extension(s)	Best for
MARC21 Binary	.mrc, .marc	Exports from most library systems and MARC tools
MARCXML	.xml, .marcxml	XML-based MARC exports and system integrations
MRK (MARC Breaker)	.mrk	MARCEdit workflows and readable MARC review
CSV	.csv	Spreadsheet catalogues and simple legacy exports
TSV	.tsv	Tab-separated legacy exports
Excel	.xlsx, .xls	Small-library catalogues maintained in spreadsheets
JSON	.json	Structured exports from custom systems or APIs

Supported output formats

Format	Extension	Notes
MARC21 Binary	.mrc	Standard MARC format for Koha import
MARCXML	.marcxml	XML MARC format supported by Koha import workflows

Koha can stage and import MARC record files. Depending on your Koha version and workflow, MARC and MARCXML are commonly used for bibliographic record import.

Notes on CSV, Excel, and TSV input

When you upload a spreadsheet or delimited file, Kai analyses the column headers and sample values, then proposes a mapping from each column to a MARC field and subfield. This mapping is presented for review before records are exported.

A few things to keep in mind:

Use clear column names. Columns such as Title, Author, ISBN, Publisher, and Publication year are easier to map than Column A or Field1.
Use one row per title where possible. This helps MARCReady identify each bibliographic record.
Separate item data where possible. Barcode, branch, location, and call number data should be kept in consistent columns.
Review the mapping carefully. Kai’s suggestions are a starting point. Local cataloguing decisions remain with the library.

Notes on MARC21 and MARCXML input

MARC21 and MARCXML files usually contain more structure than spreadsheets. MARCReady can review these records for common problems such as invalid indicators, missing fixed fields, empty subfields, and character encoding issues.

If you have access to a MARC export from your current system, use that before falling back to a spreadsheet export.

File size guidance

MARCReady is designed for practical library migration workflows. For very large catalogues — for example, institutions with hundreds of thousands of records — contact KohaSupport before uploading to discuss the best approach for your project.