Cooperative Patent Classification (CPC)

The Cooperative Patent Classification (CPC) system, in force from 1 January 2013, is a bilateral system which has been jointly developed by the EPO and the USPTO.

The CPC is subject to ongoing revision by both offices, and documents are reclassified accordingly. It is designed for efficient searching, an important aspect for users of patent information.

The CPC is the EPO's main classification scheme. When the CPC superseded the ECLA in January 2013, the ECLA and ICO schemes were flattened into one scheme.

All the breakdown and orthogonal codes were migrated to the 2000 series, by adding 2000 to the original main group digits.

The CPC is based on the IPC and consists of:

  • all IPC symbols
  • a main trunk of CPC symbols
  • a 2000 series of indexing codes for additional information

The CPC includes the same sections as the IPC, plus a Y section for tagging emerging technologies or technologies spanning several sections of the CPC.

The CPC symbol is an extension to the IPC symbol which further classifies the patent document into a specialised category. It is estimated that 90% of the documents requiring a CPC classification will receive one within eight months of publication.

For more information, including concordance tables, CPC definitions and news, visit the CPC website, which is jointly hosted by the EPO and the USPTO.

The Cooperative Patent Classification International (CPCI) project, launched on 26 August 2019, is a project jointly developed by the EPO and USPTO, in order to treat CPC allocations from the EPO, USPTO and other National Offices equally, as well as to simplify the synchronisation and conflict resolution mechanisms between the EPO and the USPTO.

As a consequence, allocations from patent offices, like EPO and USPTO, are stored at simple patent family level and the Patent office endorsing a particular allocation is visible as well as searchable. E.g. the allocation H01R 12/73 (GB) indicates that it is endorsed by the United Kingdom Intellectual Property Office and this specific allocation can be searched as explained in the section “Classification search” .

For more details on the CPCI, please send an e-mail to

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