Glossary
What is fair use?
By the KeyMo team · Updated
Fair use is a US legal doctrine that can allow limited use of copyrighted work without permission, for purposes such as criticism, comment, news reporting, teaching, scholarship or research. It is decided case by case, using four factors, and only a federal court can settle it. It is a defence you argue after the fact, not a permission you hold in advance.
Fair use definition and where it comes from
The US Copyright Office describes fair use as a legal doctrine that permits unlicensed use of copyright-protected works in certain circumstances, with Section 107 of the Copyright Act as the framework. The statute names criticism, comment, news reporting, teaching, scholarship and research as examples. They are examples, not a guarantee.
It began as a judge-made idea in the nineteenth century and was written into the 1976 Copyright Act. That history explains why there is no checklist you can pass: a judge looks at the facts of one use and weighs them.
The four factors in plain English
| Factor | The question a court asks | What the Copyright Office adds |
|---|---|---|
| 1. Purpose and character | Why did you use it, and did you add something new? | Transformative uses are more likely to be fair. Commercial use is not automatically unfair. |
| 2. Nature of the work | Is the original creative or factual? | A movie, novel or song gets more protection than a news item or technical article. |
| 3. Amount used | How much, and was it the heart of the work? | A small amount favours fair use, but a short piece can still fail if it is the heart of the work. |
| 4. Market effect | Does your use hurt sales or licensing of the original? | Courts look at present harm and at harm if the practice became widespread. |
The list is open: the statute says the factors "include" these four. No single factor wins on its own.
What fair use does not give you
- A safe length. The Office says there is no formula for a number of words, lines, pages or copies, and its page mentions no number of seconds or minutes.
- A way to decide it yourself. A third party does not have to accept your view, and only a federal court can determine whether a use is fair.
- A shield from platform claims. YouTube says Content ID cannot decide fair use, and a claim can stop monetization while you dispute it.
- Protection from credit lines. YouTube says crediting the owner or writing "no infringement intended" will not turn a copy into fair use.
A worked example with a podcast clip
Take two 40-second excerpts of the same episode. In the first, you add your own analysis and pause the excerpt to disagree with it. In the second, you post the best 40 seconds with captions and music and nothing else. Factor one favours the first, because it adds a different purpose. Factor four may hurt the second more if people watch the clip instead of the episode.
That is a way to think about it, not a ruling. Neither the Copyright Office nor the platforms read for this page say whether clipping a podcast is fair use. Where doubt remains, the Office recommends obtaining permission.
Outside the United States
This page covers the US doctrine. YouTube notes that copyright exceptions differ by country: the EU lists specific categories such as quotation, criticism, review, caricature, parody and pastiche, and some countries use fair dealing. TikTok's copyright policy names both fair use and EU exceptions. We have not checked the law in any single country, so do not treat this page as the rule for yours.
Where KeyMo touches it
KeyMo does not decide fair use for you. When you import a video by link you confirm that you own it or have permission to use it, and that is the safer starting point. Related terms: copyright claims, DMCA takedowns and Creative Commons licences.
Sources: U.S. Copyright Office: Fair Use Index (checked 11 October 2026); U.S. Copyright Office: Fair Use FAQ (checked 11 October 2026); U.S. Copyright Office: Circular 92, Chapter 1 (Section 107) (checked 11 October 2026); YouTube Help: Fair use on YouTube (checked 11 October 2026); TikTok: Intellectual Property Policy (checked 11 October 2026).