What determines fair use?

The following four factors are used to determine if a use is fair:

  1. The purpose of the use (eg. commercial vs. educational)*
  2. The nature of the copyrighted work
  3. The amount of the material used (the greater the amount copied, the less likely it is fair use)
  4. The effect of use on the potential market for or value of the work

* Not all uses in an academic context are automatically considered fair use!