Copyright in a work does not last forever. A limited duration ensures that others can use the work in creating new works. For example, a limitation on duration allows an interested person to republish old songs that have practically disappeared because the song’s publisher will not publish it or its author is unknown. The Constitution mandates a limitation on duration of copyright to ensure progress and public good.
Although copyright law has always recognized the principle of limited duration, the law governing duration has undergone drastic change over a period of time. Present copyright law created a new duration for works created after January 1, 1978. However, works created earlier are governed by different rules. The following table gives a breakdown of copyright durations for works created at different points in time.
| Date of Copyright | When Renewal Due | Duration of Copyright |
|---|---|---|
| Pre-1923 | N/A | Copyright has expired |
| 1923-1963 | During the 28th year of copyright, otherwise copyright has expired | 95 years from the date of copyright, if renewed in the 28th year |
| 1964-1977 | Renewal during the 28th year of copyright optional; if no renewal filed, automatic renewal | 95 years from the date of copyright |
| Created before 1978 but not registered or published | N/A | Author’s life + 70 years or December 31, 2002 whichever is longer |
| Anonymous, pseudonymous, and corporate-owned works created after 1977 or created but not published or registered before 1978 | N/A | 95 years from publication or 120 years from creation, whichever is sooner |
| 1978 onward | N/A | Author’s life + 70 years |