What is the International Patent Classification?

The acronym IPC stands for the International Patent Classification system and classifies patent documents on the basis of their technical content.  The classification system covers all areas of technology, and enables systematic archiving of the documents, as well as basis for searching the state of the art in chosen fields of technology.  There are approximately 70,000 different IPC symbols and are universally used throughout the world.

Each section is designated by a letter from A through to H, assigned to areas as shown in the table below.

Section Type
AHuman Necessities
BPerforming Operations; Transporting
CChemistry; Metallurgy
DTextiles; Paper
EFixed Constructions
FMechanical Engineering; Lighting; Heating; Weapons; Blasting

Each section is then sub-divided into classes which are represented as a 2-digit number.  A class title is then used to give an indication of the content of the class.  Following this, a sub-class, consisting of a capital letter and a sub-class title, is used.  A group symbol of 2 numerical digits follows the sub-class, preceded by an oblique stroke.  This can represent a main group (00), or a sub group.

Therefore, a complete classification symbol comprises of the section, class, subclass and group.  An example is shown in the diagram below.

The IPC Hierarchy

The European Classification system (ECLA) is an extension of International Patent Classification and is used by the European Patent Office to classify patent applications.