Citation generator: APA, MLA, Chicago, Harvard, IEEE, Vancouver

Enter the work once and the page writes it in eight forms: APA 7th edition, MLA 9th edition, Chicago 18th edition (author-date reference, note and bibliography entry), Harvard as defined by Cite Them Right, IEEE and Vancouver as defined by the US National Library of Medicine’s Citing Medicine with the ICMJE author limit. Italics are kept when you copy a single reference into a word processor.

What each style does with the details

• Authors. APA lists up to 20 (then the first 19, an ellipsis and the last) with initials; MLA uses one, two, or the first plus “et al.”; Chicago 18 lists up to six in a reference list or bibliography and the first three plus “et al.” for seven or more, and uses “et al.” in notes from four authors and in author-date text citations from three; Cite Them Right lists every author in the reference list and uses “et al.” in the text from four; IEEE gives initials first and switches to “et al.” above six; Vancouver lists six, then “et al.”.
• Page ranges. APA, Harvard and IEEE print the full range (207–217). Chicago abbreviates by its inclusive-numbers rule (207–17, 101–8, 1496–1500), MLA keeps at least two digits (103–04), and Vancouver drops repeated leading digits with a hyphen (207-17).
• DOIs. APA, MLA, Chicago and Harvard print https://doi.org/…; IEEE and Vancouver print doi: ….
• Place of publication. Only IEEE and Vancouver still use it.

DOI look-up

The look-up sends only the DOI to Contifield’s server, which asks the Crossref REST API for that work’s public metadata, identifies itself as Crossref asks, respects Crossref’s robots.txt and caches answers so the same DOI is not requested again for a week. Crossref covers DOIs registered with Crossref (most journals and many books); DataCite DOIs for datasets are not covered. Metadata is entered by publishers, so check names, capitalisation and page numbers before you copy.

Limits

Titles are kept exactly as typed: APA and Vancouver want sentence case for article and book titles, while MLA, Chicago and IEEE use headline case, and an automatic change would wreck proper nouns and acronyms. IEEE and Vancouver also expect the journal’s official abbreviation, which you type in the journal field. Reports, theses, films, social-media posts and legal sources have their own patterns in each manual and are not covered here; numbered styles show the number 1, which you renumber in your list.

References

• APA Style: journal article references (7th edition)
• MLA Style Center: works cited quick guide (9th edition)
• The Chicago Manual of Style Online: citation quick guide (18th edition)
• Cite Them Right Harvard quick guide (York St John University, August 2025)
• IEEE Reference Guide
• Citing Medicine, 2nd edition (NLM)
• ICMJE recommendations: references
• Crossref REST API documentation and etiquette