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Copyright Basics

Introduction to copyright protections, exceptions such as fair use, public domain, Creative Commons, and more.

Limitations to Copyright

Congress has not only established the exclusive rights of copyright but also has created exceptions and limitations to those rights. These limitations exist to encourage activities that Congress determines to be desirable and would be made difficult under copyright law. Many of these limitations are very specific in their focus, but fair use is much broader in when it can be applied. 

This Crash Course video has an overview of why limitations to copyright exist under U.S. law and some of the more common limitations, including fair use. 

What is Fair Use?

Fair use icon, the letters F and U combined in a circleFair use: "a legal doctrine that promotes freedom of expression by permitting the unlicensed use of copyright-protected works in certain circumstances (U.S. Copyright Office)"

Purpose of Fair Use

"The doctrine of fair use ... permits courts to avoid rigid application of the copyright statute when, on occasion, it would stifle the very creativity which that law is designed to foster (Iowa State University Research Foundation, Inc. v. American Broadcasting Companies)."

As the above quote from the Supreme Court states, fair use exists to allow for copyrighted materials to be used without a license in certain cases that would normally violate the exclusive rights of copyright. In these cases, the promotion of creative work that is the justification of the Copyright Clause of the Constitution is better served by not granting monopoly over the original work. 

Congress wrote into Section 107 of the Copyright Act some examples reasons that unlicensed use of copyrighted work might be fair use: "criticism, comment, news reporting, teaching..., scholarship, or research (17 U.S. Code § 107)."

Let's use a thought experiment based on one of those examples to explain the logic of fair use. You are a journalist, and you discover a document from a major corporation admitting that they are violating environmental safety laws. You want to share material from that document to report on that violation, but that document is copyrighted material owned by the corporation. The corporation is not going to give you a license to use that material, but fair use can give you the ability to copy from the document without a license. 

The Four Factors of Fair Use

Section 107 sets out 4 factors that are considered when determining when an unlicensed use of copyrighted material is a fair use:

  1. the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
  2. the nature of the copyrighted work;
  3. the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and
  4. the effect of the use upon the potential market for or value of the copyrighted work (17 U.S. Code § 107).

When trying to determine if your use of copyrighted material is fair, you have to balance the four factors against each other. While one factor may favor fair use, it could be outweighed by other factors (Crews Ch. 11 [UofM login required]).

Purpose and Character of the Use

  • Noncommercial and educational uses of materials are more likely to be fair (U.S. Copyright Office). 
    • Some uses might be mixed. A work might be commercial, which tends to not favor fair use, but also a piece of criticism, which tends to favor fair use (Crews Ch. 11 [UofM login required]). 
  • Transformative uses are also more likely to be fair. A use is transformative when it creates new meaning or adds value to the original work rather than just copying it (Stim). 
    • Whether a use is "transformative" isn't a yes or no question, as some uses can be more transformative than others, and the more transformative it is, the more likely it favors fair use (Stim).
    • Highly transformative uses cases can also affect how the other factors are analyzed (Crews Ch. 11 [UofM login required]). 

Nature of the Copyrighted Work

  • Using factual works generally gives more room for copying than fictional works, as sharing information is publicly beneficial (Stim). However, you can use fictional works under fair use, but in most cases those uses will be more limited (Crews Ch. 11 [UofM login required]). 
  • Using published work generally gives you a stronger fair use case than unpublished work, as courts have argued authors have a right to control the circumstances their work is first published, though there can be exceptions (Crews Ch. 11 [UofM login required]).

Amount and Substantiality Used

  • The first factor to consider is how much you are using.
    • Usually the more of the work used, the less likely this factor is to favor fair use.
    • However, this can also depend on the type of work being used.
    • There are also cases where whole works can be used, but generally these uses need to be very transformative (Crews Ch. 11 [UofM login required]).
  • What content you use is also a consideration, as using very important parts of a work, often called the "heart," generally leans this factor away from fair use, even if the use is very small (Stim).

Effect Upon the Market

  • If a potential use will damage the copyright owner's income or prevent them from accessing new markets for their work, then the factor will weight against fair use (Stim).
  • Changing the context of the original work, such has through providing criticism, commentary, and other educational purposes can make it less likely that the market for the original is affected (Crews Ch. 11 [UofM login required]). 
  • There are also some cases where potentially damaging the market for a work is accepted by the courts as necessary. A negative review or parody of a work could limit its sales but still would fall under fair use (Crews Ch. 11 [UofM login required]).

Resources to Help You Determine Fair Use

You might be getting a sense from the sections above that whether something is fair use is not always clear cut. This is a strength and a weakness. The broad nature of fair use allows it to be adapted to new situations and contexts much more easily than other copyright limitations, but the vagueness can make people who want to use it feel less secure in their decisions. 

These resources are designed to help you feel more secure using fair use. While they are not legal advice, they can help you think through whether what you want to do would be a fair use. 

Fair Use Checklist

This document takes you through the four factors and is designed with educational uses in mind. Use it to help you think through your fair use case. 

Fair Use Index

The Copyright Office's Fair Use Index is a search tool that tracks court decisions on fair use cases to help identify existing law. It allows you to narrow searches by legal jurisdictions and the types of works involved. It will summarize the case, but you will need to find full text of the case law elsewhere. 

Best Practices

Best practice documents can give you a sense on fair use has been and should be applied. These best practice documents are produced by the American University School of Communication's Center for Media and Social Impact (formerly Center for Social Media) and Washington College of Law's Program on Information Justice and Intellectual Property.


Crews., Kenneth D. Copyright Law for Librarians and Educators : Creative Strategies and Practical Solutions. Fourth edition, ALA Editions, 2020. EBSCOhost,

Stim, Richard. "Measuring Fair Use: The Four Factors." Stanford Copyright & Fair Use, Stanford Libraries,

United States Code. Legal Information Institute, Cornell Law School,

United States Copyright Office. "More Information on Fair Use."

United States Supreme Court. Iowa State University Research Foundation, Inc. v. American Broadcasting Companies, Inc. 12 May 1980. H20, Harvard Law School,