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IPC (International Patent Classification)

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The IPC (International Patent Classification) is one of the most important tools available to people who want to search patent databases. It divides the world of technology up into over 70 000 categories. Whatever your technical field, you can use the IPC to zoom in to patent documents relevant to your field of work.

The IPC is a hierarchical system, with layers of increasing detail. Here is an example:

G                 Physics
G02              Optics
G02C           Spectacles, sunglasses or goggles ...
G02C5          Construction of non-optical parts
G02C5/14     . Side members
G02C5/20     .. Adjustable, telescopic

New patent documents

When a patent office publishes a patent application or grants a patent, it classifies the invention using the version of the IPC in force at the time.

Reclassification of older documents

Revisions to the IPC generally take place once a year. Whenever the IPC is changed, older documents published under an earlier version are reclassified. In other words, you can search all the documents in patent databases by using the symbols of the latest IPC version.

Additional definitions

Definitions are being developed for the IPC to help understanding the scope of and the relevant references for a given subclass. In the areas where they are ready, they are made available to the public in the electronic layer of the new IPC.


WIPO is in charge of the administration of the IPC classification schemes. The text of the latest version of the IPC, including definitions, where available, can be found on the WIPO website .

All documents classified according to the IPC are stored in a Master Classification Database (MCD), managed by the EPO. This database supplies the IPC data for, among others, Espacenet.

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