Since the 1976 law and subsequent amendments in 1992 and 1998, the term of copyright protection has gotten longer and longer. The length varies by when the work was created and also depends on if/when the work was published, how many people were involved in its creation, and whether it was created in the U.S. or not.
The graphic here shows the extension of copyright protection through the Congressional Acts. At this point, we are in the purple range*.
These rules refer to works created in the U.S. since 1978.
For more specific guidelines for works created before 1978 with or without the © symbol, see the Digital Copyright Slider.
*NOTE: For the sake of illustration, this graphic assumes the author is 35 at the time of creation.
"Trend of Maximum U.S. General Copyright Term" by Tom W. Bell
Licensed under a Creative Commons Attribution-Share Alike 3.0 Unported License
Prior to the 1976 law (which took effect in 1978), works were copyrighted starting on the date they registered with the © icon for an initial period of 28 years, with the possibility of one 28-year renewal. The 1976 law extended the renewal period to 47 years, for a total term of 75 years of protection. The 1998 law (aka the Sonny Bono Act) extended the term another 20 years, for a total of 95 years (28+47+20).
(Copyright Basics, Copyright.gov [PDF])
The information presented here is for informational purposes only and should not be considered legal advice.