How to Format a DOI in APA, MLA, and Chicago: Rules, Examples, and Automation

## Stop Wasting Time on DOI Formatting You’ve found the perfect source. Now you need to add the DOI to your reference list. But the rules change depending on whether you’re using APA, MLA, or Chicago. And they keep changing every edition. Sound familiar? You’re not alone. DOI formatting is one of the most confusing parts of academic writing. One wrong slash, one missing prefix, and your entire citation could be wrong. Let’s fix that right now. ## Understanding DOI Formatting Across Styles A DOI (Digital Object Identifier) is a permanent link to a digital source. It never changes, even if the URL does. That’s why every major style guide now requires or strongly recommends including it. But here’s the catch: each style formats the DOI differently. APA 7th edition uses a hyperlink format. MLA 9th edition prefers the full URL. Chicago 17th edition gives you two options. And getting it wrong can cost you points on your paper. ### What a DOI Actually Looks Like Before we dive into styles, let’s identify a DOI. It always starts with “10.” followed by a prefix, a slash, and a suffix. Like this: - `10.1037/amp0000891` - `10.1086/723543` In older formats, you might see `doi:10.1037/amp0000891`. But modern style guides have moved away from that. ## How to Format a DOI in APA 7th Edition APA 7th edition made a major change: DOIs are now formatted as hyperlinks. No more “doi:” prefix. No more “Retrieved from.” Just the link. ### APA DOI Format Rules - Use the format: `https://doi.org/10.xxxx/xxxxx` - No period at the end of the DOI link - Hyperlink should be live (blue and underlined) in digital submissions - For print, remove the hyperlink but keep the URL ### APA DOI Examples **Journal article with DOI:** ``` Aguilar, S. J. (2021). Learning analytics and the future of education. Educational Researcher, 50(3), 145–158. https://doi.org/10.3102/0013189X21994188 ``` **Book chapter with DOI:** ``` Brown, T. (2020). Design thinking in practice. In R. Martin (Ed.), The design of business (pp. 45–67). Harvard Business Review Press. https://doi.org/10.1234/abc123 ``` ### Common APA DOI Mistakes - Adding “doi:” before the link. Don’t. APA 7th edition removed this. - Forgetting the `https://doi.org/` prefix. The DOI number alone isn’t enough. - Adding a period after the DOI. It breaks the hyperlink. For more help with APA formatting, check out The Ultimate APA 7th Edition Formatting Guide. ## How to Format a DOI in MLA 9th Edition MLA 9th edition treats DOIs as URLs. The format is simple: use the full `https://doi.org/` link, just like APA. ### MLA DOI Format Rules - Use the format: `https://doi.org/10.xxxx/xxxxx` - Place it at the end of the citation - No period after the DOI - No angle brackets or quotation marks ### MLA DOI Examples **Journal article:** ``` Aguilar, Stephen J. “Learning Analytics and the Future of Education.” Educational Researcher, vol. 50, no. 3, 2021, pp. 145–58. https://doi.org/10.3102/0013189X21994188. ``` **Book chapter:** ``` Brown, Tim. “Design Thinking in Practice.” The Design of Business, edited by Roger Martin, Harvard Business Review Press, 2020, pp. 45–67. https://doi.org/10.1234/abc123. ``` ### MLA DOI vs. URL MLA prefers DOIs over URLs. If a source has both a DOI and a URL, always use the DOI. It’s more stable and permanent. For a complete overview of MLA formatting, read our MLA 9th Edition Formatting Guide. ## How to Format a DOI in Chicago 17th Edition Chicago 17th edition gives you two options: the short form or the long form. Choose one and stick with it throughout your paper. ### Chicago DOI Format Rules **Option 1 (Short form):** `https://doi.org/10.xxxx/xxxxx` **Option 2 (Long form):** `doi:10.xxxx/xxxxx` - Chicago prefers the short form (full URL) - Place it at the end of the citation - No period after the DOI ### Chicago DOI Examples **Journal article (short form):** ``` Aguilar, Stephen J. “Learning Analytics and the Future of Education.” Educational Researcher 50, no. 3 (2021): 145–58. https://doi.org/10.3102/0013189X21994188. ``` **Journal article (long form):** ``` Aguilar, Stephen J. “Learning Analytics and the Future of Education.” Educational Researcher 50, no. 3 (2021): 145–58. doi:10.3102/0013189X21994188. ``` ### Chicago Notes-Bibliography Style If you’re using Chicago notes-bibliography, the DOI goes in the bibliography entry, not the footnote. **Footnote example:** ``` 1. Stephen J. Aguilar, “Learning Analytics and the Future of Education,” Educational Researcher 50, no. 3 (2021): 145, https://doi.org/10.3102/0013189X21994188. ``` For more on Chicago style, see the Chicago Manual of Style 17th Edition: The Ultimate Formatting Guide. ## DOI Formatting Comparison Table Here’s a quick reference for how to format a DOI in each style: | Style | Format | Example | |-------|--------|---------| | APA 7th | `https://doi.org/10.xxxx/xxxxx` | `https://doi.org/10.3102/0013189X21994188` | | MLA 9th | `https://doi.org/10.xxxx/xxxxx` | `https://doi.org/10.3102/0013189X21994188` | | Chicago (short) | `https://doi.org/10.xxxx/xxxxx` | `https://doi.org/10.3102/0013189X21994188` | | Chicago (long) | `doi:10.xxxx/xxxxx` | `doi:10.3102/0013189X21994188` | ## Pro Tips for DOI Formatting ### Tip 1: Always Use the DOI When Available DOIs are more stable than URLs. If a source has a DOI, use it. Period. This applies to APA, MLA, and Chicago. ### Tip 2: Check for Hidden DOIs Some databases hide DOIs in the article metadata. Look for a “DOI” field or check the article’s landing page. If you can’t find it, use Crossref’s DOI lookup tool. ### Tip 3: Don’t Trust Citation Generators Many citation generators get DOI formatting wrong. They might add “doi:” when they shouldn’t, or forget the `https://doi.org/` prefix. Always double-check. Learn more about why in Why Citation Engines Fail: The Case for Rule-Based Automation. ### Tip 4: Be Consistent If you choose the short form in Chicago, use it for every citation. Don’t mix short and long forms. The same goes for APA and MLA—stick to the standard format. ### Tip 5: Use Automation Tools Manually formatting DOIs is tedious and error-prone. Tools like Formatly automate the entire process. Just paste your source information, and Formatly applies the correct DOI format for APA, MLA, or Chicago. ## How to Automate DOI Formatting with Formatly Formatly takes the guesswork out of DOI formatting. Here’s how it works: 1. **Enter your source information** – Title, author, journal, DOI number 2. **Select your style** – APA, MLA, or Chicago 3. **Generate your citation** – Formatly applies the correct DOI format automatically 4. **Export to Word** – Your formatted paper, complete with proper DOIs No more manual formatting. No more style guide hunting. No more mistakes. Formatly handles all the edge cases too: - Sources with and without DOIs - Multiple authors and editors - Journal articles, books, chapters, and more - Cross-style conversions (e.g., MLA to APA) For a deeper dive into how Formatly works, check out Effortless Academic Paper Formatting. ## Stop Formatting DOIs by Hand You have better things to do than memorize DOI formatting rules for three different style guides. Your research, your writing, and your sanity deserve better. Formatly automates DOI formatting and every other citation detail. No more cross-referencing style guides. No more last-minute formatting panic. Just perfect citations, every time. **Try Formatly free today** and see how much time you save on formatting. Your next paper will thank you.