See U.S. Copyright Office for detailed information.

"Fair Use" Criteria

The statutory criteria for judging the "fair use" of copyrighted materials are:

the purpose and character of the use, including whether such use is of a commercial nature or is for non-profit education purposes,
the nature of the copyrighted works,
the amount and substantiality of the part used in relation to the copyrighted work as a whole, and
the effect of the use upon the potential market for, or value of, the copyrighted work.

Guidelines for copies

The agreement between publishers, educators, and authors set forth guidelines for librarians and teachers on making single copies. The following are allowed:

a chapter from a book
an article from a periodical or newspaper
a short story, essay, or poem, whether or not from a collected work
a chart, graph, diagram, drawing, cartoon, or picture from a book, periodical, or newspaper
a short excerpt (up to 10%) of a unit of music such as a song or movement

A librarian or teacher may also make multiple copies, not to exceed one per pupil, for classroom use of:

a complete poem of less than 250 words and printed on not more than two pages
an excerpt of less than 250 words from a longer poem
a story, essay, or article of less than 2,500 words
one illustration (chart, graph, picture, diagram, cartoon, etc.) from a book or periodical
up to 10% of a unit of music for academic purposed other than performance

A librarian or teacher may also copy a work, such as a score of music, in an emergency if one cannot be purchased in time, or may display a purchased copy of a copyrighted work through an opaque projector.

"Home use only" and/or rented videos

A librarian or teacher may show "home use only" or commercially rented videotapes if the following criteria are met:

The performance must take place in a classroom or other place of instruction in a non-profit educational institution.
The performance must be in the course of face-to-face teaching activities.
The film or video must be made from a copy of the work which was legally made or acquired.

A librarian or teacher may not do the following:

Copy from "consumable" works such as standardized tests, answer sheets, or class workbooks.
Copy commercial videotapes, audiotapes, or other like formats.
Copy in order to create anthologies or to substitute for them.
Copy on direction from higher authority.
Copy to substitute for the purchase of books, periodicals, and music.
Copy the same item from term to term without gaining permission.
Copy more than one short work or two excerpts from one author's work in a term.
Make multiple copies more than nine times in the same class term.
Make copies of music or lyrics for performance of any kind in the classroom or outside it.
Show a copyrighted videotape for entertainment purposes.
Copy protected materials without inclusion of a notice of copyright.