Copyright protection doesn’t last forever. Eventually, a work loses copyright protection and becomes part of the “public domain.” Once a work is in the public domain, it’s freely available for anyone to use.

A central purpose of copyright law is to encourage people to make creative works. For this reason, the public domain ensures copyright owners obtain certain rights only for a limited amount of time. This balance between copyright law and the public domain gives the author an incentive to create, but also gives other people the ability to use the work without permission after the copyright expires.

There are many factors that determine when a work becomes part of the public domain. Some of these factors include when and where the work was first published, the type of work and the publisher. For example, the Berne Convention, an international treaty about copyright, states that the copyright for most types of works must last at least 50 years after the author’s death. Countries, however, are free to set longer copyright terms within their own laws.