How to Find a DOI (Digital Object Identifier)

A DOI (Digital Object Identifier) is a permanent link to a scholarly source. Learning how to find and use DOIs is essential for creating accurate academic citations. This guide shows you exactly where to look.

What is a DOI?

A DOI is a unique alphanumeric string assigned to scholarly articles, books, and other research outputs. It looks like this:

DOIs are permanent — even if a journal changes its website or an article moves to a new URL, the DOI will always point to the correct source.

Why Are DOIs Important?

• Permanence: Unlike URLs, DOIs don't break or change over time
• Credibility: DOIs indicate peer-reviewed, professional publications
• Required by citation styles: APA, MLA, Chicago, and most academic styles prefer DOIs when available
• Easy verification: Readers can quickly locate your sources

Where to Find a DOI

1. On the Article or Book Page

The most common place to find a DOI is on the first page of the article or book, usually near the title or copyright information. Look for:

• Header or footer of the first page
• Near the abstract
• In the copyright section
• On the journal's website page for the article

2. Search on Crossref

Crossref is the official DOI registration agency for scholarly content. Use their search tool if you can't find the DOI on the source:

1. Go to crossref.org
2. Enter the article title, author, or journal name
3. Find your source in the results
4. Copy the DOI (it will start with "10.")

3. Google Scholar

Google Scholar often displays DOIs in search results:

1. Search for your article on Google Scholar
2. Look for the DOI in the citation information
3. Or click on the article and check the publisher's page

4. Journal or Publisher Website

If you're accessing an article through a database like JSTOR, PubMed, or ScienceDirect:

• Check the article details page
• Look in the "About this article" or "Cite this" section
• The DOI is usually listed with other publication information

DOI Formats

DOIs can appear in several formats:

All these formats work — they all point to the same source. Most citation styles prefer the numeric format (10.1000/...) or the https:// format.

Using DOIs in Citations

APA Style

MLA Style

Chicago Style

What If There's No DOI?

Not all sources have DOIs. Here's what to do:

• For journal articles without DOIs: Include the journal homepage URL or database name
• For books without DOIs: Use the ISBN if available
• For websites: Use the full URL
• For older publications: DOIs weren't widely used before the 2000s, so older sources often don't have them

Testing a DOI

To verify a DOI works correctly:

1. Go to https://doi.org
2. Enter the DOI in the search box (include or exclude "doi:" prefix)
3. Click "Go" — you should be redirected to the article's publisher page

If it doesn't work, double-check the DOI for typos. DOIs are case-sensitive and must be entered exactly as published.

Related Guides

• How to Cite a Website in APA Format
• How to Cite a Journal Article in Chicago Style
• APA vs MLA: Which to Use?