US copyright law's fair use exemption (section 107) allows use of copyrighted materials without obtaining permission under certain circumstances. There is a four-factor analysis which must be applied to each use to determine if the use is fair. Applying these four factors is not always straightforward, and all four factors need to be considered when determining if fair use applies. However, all factors do not have to favor fair use to determine that a valid fair use claim can be made.
PURPOSE & CHARACTER OF THE USE: the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes. Fair use is favored if the use is:
NATURE OF THE WORK: the nature of the copyrighted work. Fair use is favored if the work is:
AMOUNT OF THE WORK: the amount and substantiality of the portion used in relation to the work as a whole. Fair use is favored if:
MARKET EFFECT: the effect upon the potential market for or value of the copyrighted work. Fair use is favored if: