Length of Copyright Term

The length of copyright coverage (the "copyright term") can be a complex calculation under U.S. copyright law. Knowing the applicable copyright term is critical when deciding whether a particular work is in the public domain and therefore freely available to anyone to use, or is still protected by copyright. For example, under the current U.S. copyright law, works published in the U.S. before 1923 are no longer protected by copyright and are now in the public domain.

In general, published works created on or after January 1, 1978, are protected for the lifetime of the author plus 70 years. In the case of joint authorship, copyright protection continues for 70 years after the death of the last surviving author.

Works published in the U.S. before 1923 are no longer protected by copyright. Unpublished works, works published in the U.S. between January 1, 1923, and January 1, 1978, present a variety of conditions and circumstances that must be considered in calculating the copyright term. Peter B. Hirtle at Cornell University has created a useful and comprehensive table detailing copyright duration and the public domain.

Editions with Several Dates in the Copyright Notice

  • The later material may be protected.
  • The earlier material may be in the public domain.
  • Unless the original material and later revisions are clearly distinguishable, all should be treated according to the latest date of copyright.

Foreign Works

Section 104 of the U.S. copyright law, specifies that works authored in foreign countries are subject to U.S. copyright protection under specific conditions.

Published works are subject to protection if

  • on the date of first publication, one or more of the authors is a national or domiciliary, or under sovereign authority of a foreign nation that is a party to a copyright treaty to which the U.S. is a party;
  • the work is first published in the U.S. or in a foreign nation that, on the date of first publication, is a party to the Universal Copyright Convention; or
  • the work is first published by the United Nations or any of its specialized agencies, or by the Organization of American States; or
  • the work is a Berne Convention work; or
  • the work comes within scope of a Presidential proclamation.

Unpublished works are subject to protection without regard to the nationality or domicile of the author.

Special note: Foreign copyright regulations are very complex and the duration of copyright can vary significantly. Some authorities advise that it is not safe to assume that a foreign work copyrighted in the last 200 years is in the public domain.


Content in this page was used or adapted with permission from one or more institutions. Please see acknowledgements.