Patent Classification

Patent classification is a system for organizing all U.S. patent documents and other technical documents into specific technology groupings based on common subject matter. On January 1, 2013, the USPTO moved from using the United States Patent Classification (USPC) system to the Cooperative Patent Classification (CPC) system, a jointly developed system with the European Patent Office (EPO). CPC has now been adopted by many countries throughout the world.

Search Patent Classification Systems

Cooperative Patent Classification (CPC) system

The Cooperative Patent Classification (CPC) effort is a joint partnership between the United States Patent and Trademark Office (USPTO) and the European Patent Office (EPO) where the Offices have agreed to harmonize their existing classification systems (European Classification (ECLA) and United States Patent Classification (USPC) respectively) and migrate towards a common classification scheme.

CPC resources:

CPC scheme (The 2020.08 version of the CPC is now in force.)
USPTO and EPO bi-lateral CPC informational site
CPC schemes and definitions bulk data page
CPC concordance page

The CPC Notice of Changes and Editorial Corrections are the official record of change for the CPC system.

United States Classification (USPC) system

The USPC classification scheme presented is primarily for historical purposes. After the implementation of the Cooperative Patent Classification (CPC), only the plant and design classification material is updated within the USPC.

Index to USPC
Seven step strategy suggested by the Patent and Trademark Resource Center to find relevant classifications.
USPC class numbers and titles
Guides
Special guides to USPC and IPC: Environmentally Sound Technologies (EST) Concordance

Documents and reports related to the USPC Manual of Classification

Classification Orders

A Classification Order documents changes to the USPC which have occurred while maintaining the system over time. A Classification Order identifies Reclassification Project team members, USPC classifications abolished, USPC classifications established, new classification definitions and changes to existing classification definitions.

Relationships between classifications and organizations

The Patent Technology Center Directors coordinate patent examination through Art Units. The term, Art Unit, refers to the group of professionals responsible for a cluster of related patent art. Art Units are currently identified by a four digit number, i.e., 1642.

Lists of withdrawn USPTO patent publications

Withdrawn patent numbers

Classification resources