How does the U.S. use the International Patent Classification?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

The United States Patent and Trademark Office (USPTO) uses the International Patent Classification (IPC) in conjunction with its own classification system. According to the MPEP:

“In accordance with the Strasbourg Agreement Concerning the International Patent Classification, the United States is required to indicate on its issuing documents the classification symbols of the International Patent Classification 2006 (Eighth Edition), hereinafter referred to as ‘Int. Cl.’”

The USPTO maintains a concordance between the U.S. classes and subclasses and the IPC. However, it’s important to note that:

• The two systems are conceptually different in many areas
• A complete one-to-one correspondence between the systems cannot be attained
• The concordance should be used as a guide in conjunction with the IPC, not as a translation list

This approach allows the USPTO to benefit from both classification systems while meeting international obligations.