Does this need an API key?

No. It queries the public Crossref REST API at api.crossref.org, which is keyless and free. Only the work's bibliographic metadata is fetched — no account or token is required.

Which styles are supported?

APA 7th, MLA 9th, Chicago author-date, IEEE, Harvard, and BibTeX. The citation is built from the Crossref metadata (authors, title, container, volume, issue, pages, year, DOI) using the rules for each style.

What if the DOI is not found?

If Crossref returns a 404 or no metadata, the tool shows a clear error. Double-check the DOI for typos — DOIs are case-insensitive but must be complete, starting with the 10. prefix.

Does my DOI get logged anywhere by this tool?

The tool itself stores nothing; the lookup is a direct browser request to Crossref. Crossref's own API may rate-limit by IP, but no Gera server sees your query.

Why does the author list sometimes look incomplete?

Crossref metadata occasionally omits given names or lists organisations as authors. The formatter renders whatever names Crossref provides and falls back gracefully when a name part is missing.

What is the DOI to Citation Formatter?

Fetches publication metadata from the keyless Crossref REST API and renders a citation in APA, MLA, Chicago, IEEE, Harvard, or BibTeX. No API key needed; only lightweight metadata is fetched in your browser. It runs free in your browser on Gera Tools, with nothing uploaded.

DOI to Citation Formatter

Name: DOI to Citation Formatter
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

Turn a DOI into a formatted citation

Paste a DOI and this tool fetches the article’s metadata from Crossref — the registry behind most journal DOIs — and formats a citation in your chosen style. It saves you from copying author lists and page numbers by hand, and it works for any DOI registered with Crossref.

How it works

The DOI is normalised (the https://doi.org/ prefix is stripped) and sent to the keyless Crossref REST endpoint https://api.crossref.org/works/{doi}. The JSON response contains structured metadata: author (an array of family/given names), title, container-title (the journal), volume, issue, page, the issued date-parts, and the DOI itself.

The formatter then assembles a citation per style. APA uses Author, A. B. (Year). Title. Journal, Vol(Issue), pages. https://doi.org/DOI. MLA puts the title in quotes and italicises the journal. Chicago author-date and Harvard are close variants. IEEE uses numbered initials, and BibTeX produces an @article entry. Everything runs in your browser — only the metadata request leaves your device.

Notes

Crossref is the right source for journal articles and conference papers. Books and datasets registered with other agencies (DataCite, mEDRA) may not resolve here. If a lookup fails, verify the DOI starts with 10. and contains no stray spaces.

Citation style differences at a glance

The same journal article looks significantly different depending on which citation style is required. For example, a paper by Smith and Jones published in 2023 in the Journal of Example Research:

APA 7th edition Smith, J. A., & Jones, B. C. (2023). The title of the article. Journal of Example Research, 12(3), 45–67. https://doi.org/10.xxxx/xxxxxx

MLA 9th edition Smith, Jane A., and Bob C. Jones. “The Title of the Article.” Journal of Example Research, vol. 12, no. 3, 2023, pp. 45–67. https://doi.org/10.xxxx/xxxxxx

Chicago author-date Smith, Jane A., and Bob C. Jones. 2023. “The Title of the Article.” Journal of Example Research 12 (3): 45–67. https://doi.org/10.xxxx/xxxxxx

IEEE J. A. Smith and B. C. Jones, “The title of the article,” Journal of Example Research, vol. 12, no. 3, pp. 45–67, 2023.

BibTeX

@article{smith2023title,
  author  = {Smith, Jane A. and Jones, Bob C.},
  title   = {The title of the article},
  journal = {Journal of Example Research},
  year    = {2023},
  volume  = {12},
  number  = {3},
  pages   = {45--67},
  doi     = {10.xxxx/xxxxxx}
}

When Crossref metadata is incomplete

Crossref is comprehensive but not perfect. A few situations produce less complete citations:

Missing given names. Some publishers register author names as family-name only. The formatter renders what is available and leaves initials blank rather than inventing them.
No page numbers. Online-first articles often have no page range yet. The citation omits the page field rather than substituting a placeholder.
Conference papers. These are registered differently from journal articles. The container-title may be the proceedings name, and volume/issue fields are often absent. The formatted citation will reflect what Crossref has.
Preprints. Preprints on arXiv, bioRxiv, and similar servers often do not have Crossref DOIs — they use their own registrar. Entering an arXiv ID directly will fail; look for the published version’s DOI instead.

If you need a citation for a work that is not in Crossref, the DOI resolver at doi.org can still redirect you to the publisher’s page where you can copy metadata manually.