Patents and Trademarks

Citation style

How to cite a patent (or a patent application) will depend on the citation style you are using. Below are some examples using common citation styles, including: ACS, APA, Chicago, IEEE, and MLA.

All examples use are based on U.S. Patent 4,378,116 Spatial Logical Toy (The Rubik's Cube).

Pay special attention to:

• Patent number - patent citations should include the "full" patent number, which may include the country code of origin, the year of publication, and the "kind" code. A kind code (e.g., B1, A) is generally added to the end of a patent or patent application and identifies the status of the patent at the time it was cited.
• Patent title/name - a patent's title (or name) can vary depending on where/how you found it. Some patent databases modify titles to make searching easier. To avoid confusion, it is good practice to cite the patent title/name that appears on the PDF of the actual patent document.

ACS (American Chemical Society)

Formats:

For all formats below: CC = Country Code, 12345678 = Patent Number, and KC = Kind Code.

Published patent.:

[Inventor 1]; [Inventor 2]; ...; [Last Inventor]. [Patent Title]. [CC12345678KC], [Publication Year].

Patent application:

[Inventor 1]; [Inventor 2]; ...; [Last Inventor]. [Patent Application Title]. [CC12345678KC], [Publication Year].

Published patent with assignees:

[Inventor 1]; [Inventor 2]; ... [Last Inventor], Inventors; [Assignee 1]; [Assignee 2]; ... [Last Assignee], Assignees. [Patent Title]. [CC12345678KC], [Publication Year].

Published patent from a database (for a translated patent citation):

[Inventor 1]; [Inventor 2]; …; [Last Inventor]. [Patent Title]. [CC12345678KC], [Publication Year]. (Provided by [name of database, accession/record identification number or URL].)

Example:

Rubik, E., Inventor; Politoys Ipari Szövetkezet, Assignee. Spatial Logical Toy. US4378116, March 29, 1983.(Provided by Google Patents, https://patentimages.storage.googleapis.com/39/b9/a0/174c807535378b/US4378116.pdf.)

Source:

ACS Guide to Scholarly Communication: 4.3.5.12. Patents

APA (American Psychological Association)

Format:

Inventor, A. A. (Year patent issued). Title of patent (U.S. Patent No. ###). U.S. Patent and Trademark Office. URL

Example:

Rubik, E. (1983). Spatial logical toy (U.S. Patent No. 4,378,116). U.S. Patent and Trademark Office. https://patentimages.storage.googleapis.com/39/b9/a0/174c807535378b/US4378116.pdf

Source:

Purdue Online Writing Lab (OWL): APA Style (7th Edition), APA Formatting and Style Guide (7th Edition), Legal References

Chicago (The Chicago Manual of Style)

Formats:

Notes and bibliography style: Patents are cited under the names of the creators, a description of the patent, and the year of filing. Include a URL for patents consulted online.

Author-date style: Patents and other documents that include more than one date should repeat the year (in this case, the year of issue) to avoid ambiguity:

Examples:

Notes and bibliography style: 
Runik, Ernö. Spatial logical toy. US Patent 4,378,116, filed August 3, 1981, and issued March 29, 1983. https://patentimages.storage.googleapis.com/39/b9/a0/174c807535378b/US4378116.pdf
Author-date style:
Runik, Ernö. 1983. Spatial logical toy. US Patent 4,378,116, filed August 3, 1981, and issued March 29, 1983. https://patentimages.storage.googleapis.com/39/b9/a0/174c807535378b/US4378116.pdf

Source:

The Chicago Manual of Style Online (18th edition): 14.158 Patents

IEEE (Institute of Electrical and Electronics Engineers)

Formats:

J. K. Author, “Title of patent,” U.S. Patent x xxx xxx, Abbrev. Month, day, year.

J. K. Author, “Title of patent,” Country Patent xxx, Abbrev. Month, day, year.

(Note: Use “issued date” if several dates are given.)

Example:

E. Rubik, "Spatial logical toy," U.S. Patent 4 378 116, Mar. 29, 1983.

Source: 

IEEE Reference Style Guide for Authors, V 3.28.2025

MLA (Modern Language Association)

Format:

To cite a patent, follow the MLA format template. List the owner of the patent in the “Author” slot, the title of the patent or a description in the “Title of source” slot, the number of the patent, the name of the agency issuing the patent in the “Publisher” slot, and the date of issue in the “Publication date” slot. If you found the patent online, include the title of the website as the title of the second container and provide the URL as the location:

Example:

Rubik, Ernö. Spatial logical toy. US 4378116, United States Patent Office, 29 March 1983.Google Patents, https://patentimages.storage.googleapis.com/39/b9/a0/174c807535378b/US4378116.pdf

Source:

MLA Style Center: How do I cite a patent? (2018)