Fair use is a part of U.S. copyright law that allows limited use of copyrighted material without the owner’s permission for purposes such as criticism, comment, news reporting, teaching, scholarship and research. It is not a fixed list of allowed uses. Courts decide each case by weighing four factors set out in Section 107 of the Copyright Act.
Key takeaways
- Fair use is a defense decided case by case, not an automatic right.
- The purpose of the use and its effect on the market for the original usually weigh most.
- Giving credit or using only a few seconds does not by itself make a use fair.
The four fair use factors
1. Purpose and character of the use
Courts ask whether the new use is commercial or nonprofit and educational, and whether it is transformative: does it add new expression, meaning or purpose instead of simply replacing the original? A review quoting a few lines to criticize a book is transformative. Since the Supreme Court’s 2023 decision in Andy Warhol Foundation v. Goldsmith, adding new meaning is not enough on its own if the new work serves substantially the same commercial purpose as the original.
2. Nature of the copyrighted work
Using factual works, such as news articles or technical material, is more likely to be fair than using highly creative works like novels, songs or films. Using unpublished works weighs against fair use, because the author has the right to decide when to publish.
3. Amount and substantiality used
Using less is generally better, but quality matters as much as quantity. Taking a small part that is the “heart” of the work can weigh against fair use, while copying more may be acceptable when necessary for the purpose, as in parody, which must conjure up the original to make its point.
4. Effect on the market for the original
Courts ask whether the use harms the market for the original or for licenses of it. A use that substitutes for buying the original, or for a licensing market the owner would normally exploit, usually weighs heavily against fair use.
Fair use examples
| Use | Likely outcome | Why |
|---|---|---|
| Quoting short passages in a book review | Usually fair | Criticism, small amount, no market substitute |
| Parody that comments on the original song | Often fair | Transformative commentary (Campbell v. Acuff-Rose, 1994) |
| A teacher copying a short excerpt for one class | Often fair | Nonprofit education, limited amount |
| Using a full song as background music in an ad | Usually not fair | Commercial, entire work, replaces a license |
| Reposting a full news article on your blog | Usually not fair | Copies everything, substitutes for the original |
Common fair use myths
- “I gave credit, so it is fine.” Attribution helps avoid plagiarism but is not a copyright defense.
- “Anything under 30 seconds or 10% is allowed.” No such rule exists in the law.
- “It is nonprofit, so it is fair.” Nonprofit use helps under the first factor but does not decide the case.
- “It is on the internet, so it is public domain.” Most online content is protected by copyright automatically.
What about AI and fair use?
Whether training artificial intelligence on copyrighted works is fair use is being tested in several U.S. lawsuits, and courts have not reached a settled answer. Results so far depend heavily on how the material was obtained and whether the outputs compete with the originals. Expect this area to keep developing.
How to reduce your risk
- Use only what you need for your purpose, and add your own commentary or analysis.
- Link to the original instead of copying it in full.
- Prefer licensed, public domain or Creative Commons material where the license fits your use.
- Ask for permission when the use is commercial or central to your project.
Frequently asked questions
Is fair use the same as public domain?
No. Public domain works are no longer protected by copyright, so anyone can use them. Fair use applies to works that are still protected.
Can I use a copyrighted image if I credit the photographer?
Credit alone does not make it legal. Unless fair use applies or you have a license, you need permission.
Does fair use apply outside the United States?
Fair use is a U.S. doctrine. Other countries have narrower “fair dealing” or specific exceptions, so the answer may differ abroad.
Fair use is fact-specific. For a commercial project, an intellectual property attorney can assess the risk. Trademarks follow different rules; see how to trademark a business name.