Free tool

BibTeX Validator

Paste a .bib file. The page reports missing fields, unknown types, duplicate keys, and years that are not four digits.

Free12 entry typesDuplicate keysRuns in the browser

The entry

@article{knuth1984,
  author = {Knuth, Donald},
  title  = {Literate Programming},
  year   = {1984}
}

The report

knuth1984
  missing journal

An @article needs author, title, journal, and year. This one has no journal, so it fails before BibTeX does.

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BibTeX input0 entries

BibTeX input

Report

Paste a .bib file, then validate.

What the check looks for

Each type has a set. A blank author on an article is an error. A book needs an author or an editor.

The same citation key twice is an error. BibTeX keeps the last definition and stays quiet about it.

Year has to be four digits. Pages should contain a number. An article with no DOI or URL is a note, not a failure.

The check runs in this browser. The file is not uploaded.

These are the twelve types this page knows. Anything else, including common BibLaTeX types such as @online, is reported as unknown.

Entry type	Required fields	Optional fields
@article	author, title, journal, year	volume, number, pages, month, doi, url
@book	title, publisher, year, author/editor	volume, series, edition, address, isbn, doi
@inproceedings	author, title, booktitle, year	pages, address, publisher, doi
@conference	author, title, booktitle, year	pages, address, publisher
@phdthesis	author, title, school, year	address, month, type, doi
@mastersthesis	author, title, school, year	address, month, type
@techreport	author, title, institution, year	type, number, address, month
@misc	None	author, title, year, url, note, howpublished
@unpublished	author, title, note	year, month
@proceedings	title, year	editor, publisher, address, volume
@manual	title	author, organization, year, edition
@incollection	author, title, booktitle, publisher, year	editor, chapter, pages, address

Bibliography checkerField rules for BibTeX and the BibLaTeX types this page does not cover.
Citation error checkerUndefined citations and keys that never appear in the document.
How to create a bibliographyThe \bibliography command and where the .bib file has to sit.
BibTeX vs BibLaTeXWhich entry types belong to which system.
How to add citations\cite and the key that has to match an entry.
Thesis and paper templatesFormatting taken from each template's own class file.

This page checks a file you paste in. In the editor, the bibliography sits in the same project as the draft.