What is a DOI?
A DOI, or digital object identifier, is a unique alphanumeric string assigned to an online document such as a journal article or ebook. A DOI can be used in a similar way to a URL, but it is more permanent and reliable.
Because a DOI never changes, academic citation styles recommend using DOIs instead of URLs to locate sources when possible.
DOIs can be formatted in various ways:
How to find a DOI
The DOI will usually be clearly visible when you open a journal article on a database.
Examples of where to find DOIs
*Note that JSTOR uses a different format, but their “stable URL” functions the same as a DOI.
What to do when you cannot find the DOI
If you cannot find the DOI for a journal article, you can also check Crossref. Simply paste the relevant information into the “Search Metadata” box to find the DOI. If the DOI does not exist here, the article most likely does not have one; in this case, use a URL instead.
Using DOIs in citations
You may need to use DOIs when citing online journal articles or certain books. Follow the standard rules for citing that type of source in your citation style, and place the DOI in the space where the URL would usually go.
APA citation with DOI
In APA, you may use the following DOI formats:
- https://doi.org/10.1177/0269881118806297 (recommended)
You can use Scribbr’s free citation generator to easily cite journal articles using the DOI. All relevant information is automatically retrieved and correctly formatted according to the citation style.
Scribbr APA Citation Generator
MLA citation with DOI
MLA recommends using the format doi:10.1177/0269881118806297.
Scribbr MLA Citation Generator
Chicago citation with DOI
In Chicago style, the format https://doi.org/10.1177/0269881118806297 is preferred.
Frequently asked questions about DOIs
- Why are DOIs important?
Journal articles and ebooks can often be found on multiple different websites and databases. The URL of the page where an article is hosted can be changed or removed over time, but a DOI is linked to the specific document and never changes.
- How do I find the DOI of an article?
The DOI is usually clearly visible when you open a journal article on an academic database. It is often listed near the publication date, and includes "doi.org" or "DOI:". If the database has a "cite this article" button, this should also produce a citation with the DOI included.
If you can't find the DOI, you can search on Crossref using information like the author, the article title, and the journal name.
- How do I format a DOI in APA style?
The old guidelines were to present DOIs by writing “doi:” followed by the numerical string. For example:
If you’re following the 6th edition, this format is still accepted, as long as it's used consistently.
- When should I include a DOI or URL in an APA journal citation?
If an article has no DOI, and you accessed it through a database or in print, just omit the DOI.
If an article has no DOI, and you accessed it through a website other than a database (for example, the journal’s own website), include a URL linking to the article.