Short answer
In US usage, copyright gives qualifying works legal protection for a limited period. Public-domain material can be used without permission under copyright law because that protection does not apply or has ended. Determine the status of the particular work; being available online does not make it public domain. 1 2
These describe different copyright statuses of material, with scope depending on the particular work and jurisdiction.
On this page
At a glance
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| Question | Copyright | Public domain |
|---|---|---|
| Copyright permission | Often needed for protected uses unless an exception applies | Not needed under copyright law for public-domain material |
| Duration | Limited, with rules varying by work | No current copyright term for that material |
| What it describes | Legal rights in a qualifying work | Absence or expiration of those rights |
The table summarizes the cited definitions and the article’s stated scope. 1 2
What each thing is
Copyright. A set of legal rights in an original work of authorship fixed in a tangible form. 1
Public domain. The status of material no longer protected by copyright or not eligible for such protection in the relevant jurisdiction. 2
Key differences
Copyright arises for original authorship fixed in a tangible form, while mere ideas are not protected as such. Protection length depends on facts such as creation and publication dates and authorship type. When copyright expires, the material enters the public domain under US law; other legal issues can still matter. 1 2
How to tell them apart
Identify the exact work and its author, date, publication history and jurisdiction. Check whether copyright could still subsist before treating it as public domain. A copyright notice is a useful clue but its absence is not proof of public-domain status for a modern work. 1 2
Where they overlap
The same work can move from copyrighted status to public-domain status over time. A new copyrighted adaptation may contain older public-domain material; the underlying and new expression require separate analysis. 1 2
Edge cases
Some material was never protected, while some works have complicated ownership or duration histories. Public domain in one country does not automatically establish the same status elsewhere. Trademark or privacy rules may still constrain a particular use. 1 2
Why the distinction exists
The limited term balances an author’s exclusive rights with eventual broad public use of expression. The public domain is the part of the cultural record not subject to current copyright restrictions. 1 2
Common misconceptions
“Free to view” and “free to use” are different. A work on a public website can remain copyrighted; a public-domain work may appear inside a copyrighted edition. 1 2
Examples
An old book whose US copyright has expired can be reproduced as public-domain text. A modern translation of that book may have its own copyright in the new wording. 1 2
Sources
Sources checked October 3, 2026.
- U.S. Copyright Office — What is Copyright?. What does copyright protect?.
- U.S. Copyright Office — How Long Does Copyright Protection Last?. Duration FAQ.