In the US copyright law, there are two essential concepts that authors have to pay attention to: fair use and copyright infringement. Fair use refers to the unauthorized use of copyrighted materials that is not viewed as a copyright infringement. On the other hand, copyright infringement is the unauthorized use of the same materials that encroaches on the exclusive rights of the copyright holder.


To simplify the definition of both fair use and infringement, the former is the unauthorized use of any work that does not violate the owner’s copyright while the latter is the opposite. Both of these concept does not have the permission from the copyright holder to use the work. However, only infringement will be liable to the copyright holder.


Fair use and infringement can also be identified through the purpose they are used. For fair use, despite the unauthorized use, it is supposed to further the copyright’s purpose. However, infringement is the exact opposite. In fact, most unauthorized use that can be labeled as copyright infringement are those that either misrepresent the original intent of the masterpiece or derive personal profit without the copyright holder’s permission.

Effect on the Market Value

How the material is used will have an impact on the market. It will be fair use if that particular usage of one’s work does not harm the owner’s potential market. It will be infringement if otherwise.

Four Factor Test

Although there is no clear test on how to evaluate if the use is fair use or infringement, there are four factors that can at least shed light on that matter.

1. Character and Purpose of Use

This examines whether the use of the work is for nonprofit purpose or commercial purpose. If it is commercial purpose, it is highly likely that the court will find it against fair use.

2. Nature of the Copyrighted Material

The closer the appropriation of that work is to the original nature of the copyrighted material, the more it will be against fair use.

3. Substantiality/Amount of Portion Used

This factor considers the percentage or amount of work used. Of course, it will also consider just how essential that portion is. If it is a trivial portion, then it may not be beyond the bounds of fair use.

4. Effect on the Market Value of the Work

It will be infringement if the unauthorized work affects the potential market negatively.

These four factors are also used in court when legal cases are filed for copyright infringement and the defendant please for fair use. Of course, these factors should be applied on a case-to-case basis. To avoid facing copyright infringement issues with your work though, be sure that you understand fair use first before you copy or use other people’s work. Better yet, get permission to use their masterpiece ahead of time.