Maximilian Marcoll just launched this site (including an API, with an ICS calendar view) which tracks the death anniversary of composers and when their work will be entering the public domain:
DeadComposers.net announces the last death anniversaries of composers before their works enter the public domain.
International copyright law protects the works of artists and composers for a certain amount of time after their deaths. When that time has passed, they automatically enter the public domain (on the next first of January), which renders them available for use by anyone without the need to worry about licensing.
While the question whether a certain work is in the public domain or not has to be answered for each work individually, the dates published by DeadComposers.net should provide a useful hint as to when it might make sense to check the legal status of a composer’s work.
DeadComposers.net is not meant as a complete resource and doesn’t try to cover all composers within the relevant time frame. There will be errors, even perhaps some composers missing. That being said – with around 20k entries in the database and considering national copyright regulations of almost 200 countries, I hope not to leave out too many dead composers.
DeadComposers.net was built as an art project in the hope that artists and composers who – like me – work with material by others, will appreciate a way of exploring who’s work can be used freely and when. The concept of intellectual property is not uncontroversial and many of us do not care much about licensing issues. Some artists are even prevented from implementing their ideas because of copyright regulations. Please consider this website an attempt to ease the pain.