How to cite a patent
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Last updated: April 4, 2026
Key Facts
- A patent citation typically includes inventor, title, patent number, date, and issuing body.
- Patent numbers are unique identifiers assigned by the patent office.
- The issuing authority is usually the national patent office (e.g., USPTO in the US).
- Key dates can include the application filing date or the grant/issue date.
- Consistency with a specific citation style guide (APA, MLA, Chicago) is crucial.
Overview
Citing a patent is essential when you refer to or build upon the information contained within it in your own work, whether it's an academic paper, a legal brief, or a technical report. Proper citation allows your readers to locate the original patent document, verify your claims, and understand the prior art. Patents are unique legal documents that grant exclusive rights to an inventor for a limited time, and citing them correctly acknowledges their significance and ensures academic or professional integrity.
Why Cite Patents?
Citing patents serves several critical purposes:
- Verification and Traceability: Allows readers to find the exact patent document you are referencing, ensuring the accuracy of your information.
- Acknowledging Prior Art: Recognizes the existing inventions and intellectual property, demonstrating an understanding of the field.
- Supporting Arguments: Provides evidence for claims made in your work, especially in fields like engineering, technology, and law.
- Avoiding Plagiarism: Gives credit to the inventor and the patent office for their intellectual contribution.
Essential Components of a Patent Citation
While specific formats vary depending on the citation style guide you are following (e.g., APA, MLA, Chicago, or a specific legal citation manual), most patent citations include the following core pieces of information:
1. Inventor(s) Name(s)
List the name(s) of the inventor(s) as they appear on the patent document. If there are multiple inventors, follow the order listed on the patent.
2. Patent Title
Include the official title of the patent. This helps to identify the subject matter of the invention.
3. Patent Number
This is a unique identifier assigned by the patent office. It is crucial for locating the specific patent. Patent numbers often have prefixes or suffixes indicating the type of patent or the country.
4. Date Information
Patents have several important dates. The most commonly cited dates are:
- Issue Date (or Grant Date): The date the patent was officially granted by the patent office.
- Application Filing Date: The date the patent application was submitted to the patent office.
- Publication Date: The date the patent application or the granted patent was made public.
Your citation style guide will specify which date(s) to include.
5. Issuing Authority
Indicate the patent office that granted the patent. This is typically the national patent office, such as the United States Patent and Trademark Office (USPTO), the European Patent Office (EPO), or the Japan Patent Office (JPO).
6. Country Code (Often Implicit or Explicit)
The patent number itself often implies the country (e.g., US patents, EP patents), but sometimes it's explicitly stated or part of the issuing authority's name.
Common Citation Styles for Patents
1. APA Style (American Psychological Association)
APA style is commonly used in social sciences and education. For patents, the format generally is:
Inventor, A. A. (Year). Title of patent (Patent No. X,XXX,XXX). Issuing Office.
Example:
Smith, J. Q. (2020). Method for data encryption (U.S. Patent No. 10,123,456). U.S. Patent and Trademark Office.
Note: APA 7th edition recommends citing the issue date. If the patent number is very long or complex, you might also include the filing date in parentheses after the patent number.
2. MLA Style (Modern Language Association)
MLA style is frequently used in the humanities. The format tends to be:
Inventor Last Name, First Name. "Title of Patent." Patent Number. Issuing Office, Date of Patent.
Example:
Jones, Sarah L. "Apparatus for Solar Energy Conversion." U.S. Patent 9,876,543. U.S. Patent and Trademark Office, 15 Jan. 2019.
MLA may also cite the application filing date if it provides additional important context.
3. Chicago Style (The Chicago Manual of Style)
Chicago style offers two systems: Notes and Bibliography, and Author-Date. The bibliography entry for a patent often looks like this:
Inventor Last Name, First Name. "Title of Patent." Patent Number. Date of Patent. Issuing Office.
Example:
Chen, Wei. "Smart Thermostat System." U.S. Patent 11,223,344. January 20, 2022. U.S. Patent and Trademark Office.
In a footnote or endnote, you might include more details like the application filing date.
4. Legal Citation (Bluebook)
Legal professionals often use specific citation manuals like The Bluebook: A Uniform System of Citation. The Bluebook has detailed rules for citing various types of legal documents, including patents. A typical Bluebook citation might look like:
U.S. Patent No. X,XXX,XXX, inventor(s) (date).
Example:
U.S. Patent No. 10,567,890, issued to Inventor Name (Jan. 1, 2021).
Bluebook citations prioritize clarity and legal precision, often including the patent's status (e.g., pending, expired) if relevant.
How to Find Patent Information
You can typically find all the necessary information directly on the patent document itself. Most patent offices provide searchable online databases:
- USPTO (United States): Available at uspto.gov
- EPO (Europe): Espacenet database
- WIPO (World Intellectual Property Organization): PATENTSCOPE database
- Google Patents: A comprehensive search engine for patents worldwide.
When accessing a patent online, look for the header or cover page, which usually contains the inventor(s), title, patent number, and key dates.
Tips for Accurate Patent Citation
- Be Consistent: Choose a citation style and stick to it throughout your document.
- Check the Patent Document Carefully: Ensure you have transcribed all information accurately, especially patent numbers and inventor names.
- Consult the Style Guide: Always refer to the specific edition of the style guide you are required to use for the most up-to-date and precise formatting rules.
- Consider Your Audience: If writing for a specific field (like law), use the conventions common in that field.
By following these guidelines, you can ensure your patent citations are accurate, complete, and professionally presented.
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