Archer Library: Engineering: Patent Classification Systems

Introduction

Patent classification systems organize patent documents by subject/class. Identifying classification numbers can assist in the efficient retrieval of patents, and assist in more thorough and exhaustive searching for patents by technological subject/concept that is sometimes necessary.

Key Search Tools

Cooperative Patent Classification (CPC)
A patent classification system developed by the European Patent Office (EPO) and the USPTO. Contains approximately 200,000 subgroups.

Search Espacenet
Search USPTO

International Patent Classification (IPC)
A hierarchical classification system consisting of about 70,000 subgroups. It is used by more than 100 patent offices to classify patent documents. IPC codes are searchable in most patent databases.