Patent classification helps conduct searches

The patent classification is your key to technical information, especially when "words are not enough". It is an internationally agreed way of defining which field of technology a specific invention belongs to.

Each patent document bears on its front page the marking Int.Cl.7. The figure in it may vary, but in all cases it tells you that the invention has been classified according to the International Patent Classification.

The importance of a patent classification has not diminished in the era of electronic access even though classification was first to exist. In the days of manual searching, classification was the only means of organizing documents in a way that enabled search of earlier, similar inventions from the vast collections of patent documents. In electronic search, a simple word search may retrieve a great number of hits. The search can be narrowed with the help of a suitable patent classification.

Our Internet databases facilitate the use of patent classification in searches.

International Patent Classification (IPC)

The International Patent Classification is the most widely used classification. It has earlier been revised every five years, since 2011 every year. The first version was taken into use in 1970 and the latest in 2011. IPC can be used in searches in espacenet (search field IPC Classification).

More information about the classification can be found on the World Intellectual Property Organization website.

International Patent Classification 2011. See "Version" in the left hand column for more information about the earlier versions 1-8.

Under "Catchwords" there is a small list of search words where you can try to find suitable classes.

Cooperative Patent Classification (CPC)

You can use the CPC classification system instead of the International Patent Classification (IPC) in database searches. In the Espacenet database, for instance, there is a specific field for the CPC. As not all patent documents in the world have been classified using the CPC, you might not find all relevant information when searching with the CPC. Please note however that the CPC divides technical fields into smaller groups, which is why the search result is more precise than when using the IPC. We recommend that you try both classification systems, at least if the search results do not contain the information you were looking for.

In the IPC, the complete range of technical fields is divided into more than 70,000 groups, while the CPC divides the fields into 250,000 groups. As a result, the CPC introduces a precise and usable search tool for information seekers.

Please note that you can only use the CPC to search documents from certain specific countries. The classification code is not shown in the patent documents, and it can only be used in online searches. The European Patent Office (EPO) and the US Patent Office (USPTO) classify their patent documents using the CPC. The EPO also classifies the patent documents of countries included in the minimum documentation, as referred to in the international Patent Cooperation Treaty (PCT), by the CPC. Such countries or organisations are Germany, France, United Kingdom, Switzerland, the World Intellectual Property Organization (WIPO, a United Nations agency) (PCT documents), Russia and Japan.

Definition of PCT minimum documentation
CPC classification system
Read more about Cooperative Patent Classification (CPC)