Fair use is the concept that describes the limited copying that is allowed under the U.S. copyright law without the permission of the owner. While there are educational guidelines, there are no legal rules permitting the use of a specific number of words, a certain number of musical notes or amount of any work. The basis for fair use is written in section 107 of the U.S. Copyright Act.
To qualify, an instance of copying depends on the circumstances. Answer these 4 questions (descriptions below) to see if fair use applies to your situation.
Think about why you want to use the work. Look at the chart below and see where your use falls on the continuum from favoring fair use to opposing fair use.
Teaching (including multiple copies for classroom)
Research
Scholarship
Nonprofit Educational Institution
Criticism
Comment
News Reporting
Transformative or productive use (changes the work for new utility)
Restricted Access (to students or other appropriategroup; i.e. Blackboard site)
Parody
Commercial
Profiting from the use
Entertainment
Bad-faith behavior
Denying credit to the original author
Think about the work you'd like to use. Look at the table below and think about where it falls on the continuum.
Unpublished work
Highly creative work (art, music, novels, films, plays)
Fiction
Think about how much you'd like to use of the work. Look at the table below and think about where it falls on the continuum.
Small amount
Portion used is not central or significant to entire work
Amount is appropriate for favored educational purpose
More than a small amount
Portion used is central to work or "heart of the work"
Think about the effect on the market for the original work or for permissions if the use were widespread. Look at the table below and think about where it falls on the continuum.
After evaluation of the first three factors, the proposed use is tipping toward fair use but must meet market test.
User owns lawfully acquired or purchased copy of original work.
One or few copies made.
Copying is one time occurrence.
No significant effect on the market or potential market for copyrighted work.
No similar product marketed by the copyright holder.
Lack of licensing mechanism.
Copyright owner is unidentifiable.
No ready market for permission.
Original is out of print
Competes with (takes away sales from) the original.
Numerous copies made.
Repeated or long term use.
Significantly impairs market or potential market for copyrighted work or derivative.
Avoids payment for permission (royalties) in an established permissions market.
Reasonably available licensing mechanism for use of the copyrighted work.
Affordable permission available for using work.
You made it accessible on web or in other public forum.