DOI Finder

How to Use the DOI Finder

1. 1. Paste your reference list. Any style works — APA, MLA, Chicago, Vancouver — one reference per line or separated by blank lines. References that already carry a DOI are left alone.
2. 2. Press Find DOIs. Each reference goes to Crossref's search in turn, about one a second, and results appear as they arrive. Up to 25 references per run.
3. 3. Check each match. A confident match is ticked for you; a possible match is shown but left unticked. Compare the Crossref record with your reference and untick anything that is not the same work.
4. 4. Copy or download the list. Accepted DOIs are added at the end of their references, and everything else is returned as you pasted it.

How a Match Is Judged

Crossref's bibliographic search takes a whole reference as you typed it and returns the records it thinks most likely. Its relevance score ranks those records against each other but does not say whether any of them is right, so the top three are each checked against your reference the way you would check them yourself:

• Title words. The share of the record's title words that appear in your reference, ignoring small words such as the and of, and allowing for a subtitle your reference leaves out.
• First author. Whether the record's first surname appears near the start of your reference.
• Year. Whether the record's year appears in your reference. One year off counts as close, because articles are often published online a year before their print issue.

A match is confident when at least 90% of the record's title words are in your reference, the first author matches (or Crossref lists none) and the year is not off by more than one. It is possible when two-thirds of the title words are there but something else disagrees, and anything less is reported as no match. Records about another record — a reply, a correction, an erratum, a retraction notice — share the original's title words, so a title carrying such a word that your reference lacks counts for less.

When There Is No DOI

Not finding a DOI is often the right answer. Most books, chapters, reports and theses, much grey literature, conference papers that were never registered and many older works have no DOI at all. Crossref covers the DOIs that publishers register with Crossref; datasets and some preprints are registered with DataCite instead and will not be found here. In APA 7 a reference with no DOI simply ends without one — add a URL only when you read the work online somewhere other than an academic database.

The DOI goes after the reference's closing full stop, with no full stop after it, as APA 7 sets it out. If a reference ends with a database link — or “Retrieved from” and a link — the DOI replaces it, because APA 7 gives the DOI instead of a database URL. MLA puts a comma before the DOI and Vancouver writes doi: 10.…, so adjust the result if your list is not in APA.

Frequently Asked Questions

How do I find the DOI of an article?

Paste the reference into the DOI Finder: it searches Crossref, the agency that registers most journal DOIs, and shows the best match beside your reference for you to confirm. You can also search the title at search.crossref.org, look on the article's web page or the first page of its PDF, or check the database record where you found it.

Why was no DOI found for my reference?

Most often because the work has none: books, chapters, reports, theses and much older or grey literature usually have no DOI. Otherwise the reference may be too incomplete for the search — a missing title or a misspelled author — or the DOI may be registered with DataCite rather than Crossref, as many datasets and some preprints are.

What is the difference between a confident and a possible match?

A confident match has at least 90% of its title words in your reference, a first author that matches and a year that agrees or is one year off. A possible match shares at least two-thirds of the title words but fails another check — a different year often means a reprint, a later edition or a notice about the article. Possible matches are added only if you tick them.

Can I trust the DOIs it finds?

Check them — that is why each match is shown with its record and its three checks, and only confident matches are pre-selected. Tested on real Crossref results, it chose the right DOI for journal articles and declined to pre-select a published reply that shared an article's title words, or a 2025 repost of a 2017 paper. A quick look at each match is still worth it before a reference list goes out.

How should a DOI look in APA 7?

As a link: https://doi.org/ followed by the DOI, at the end of the reference and with no full stop after it — for example https://doi.org/10.1007/s11192-006-0144-7. APA 7 replaced the older doi: label and the “Retrieved from” wording. How to Use DOIs in APA, MLA, and Chicago Citations covers the other styles.

What is sent to Crossref?

Each reference's text, without its list number or any link, goes from your browser to Crossref's public search at api.crossref.org — nothing else, and nothing to CitationEasy. Crossref limits how fast anonymous searches may run, which is why the tool waits about a second between references.