A classification system is an arrangement of hierarchical categories used to organize things by their characteristics or relationships. A patent classification system has as its primary purpose the establishment of an effective search tool for patent document retrieval by intellectual property offices and other users, in order to establish the novelty and evaluate the inventive step of technical disclosures in patent applications.

In a patent classification system, patents are classified according to the different areas of technology to which they pertain. Patent classes are deconstructed into detailed “sub” levels. The layout of the classification symbols may include Section, Class, Subclass, Group, and/or Subgroup.

Typical example of IPC or CPC classification symbol: A45B 19/08

A section
A45 class
A45B sub class
A45B 19/00 main group
A45B 19/08 sub group

There are several patent classification systems. Among them, the Corporate Patent Classification system (CPC) and International Patent Classification system (IPC or Int.Cl) are the most prevalent, and are used by patent offices worldwide including USPTO, WIPO, and EPO, as well as commercial patent databases.

Things to remember:

• CPC has the same general hierarchical structure as that of the IPC. CPC has more subgroups or breakdowns than IPC.
• The CPC scheme includes the same eight sections (A to H) as IPD.  However, CPC has an additional Y section.

Section A – Human Necessities
Section B – Performing Operations; Transporting
​Section C – Chemistry; Metallurgy
Section D – Textiles; Paper
Section E – Fixed Constructions
Section F – Mechanical Engineering; Lighting; Heating; Weapons; Blasting
Section G – Physics
Section H – Electricity

Section Y -- General tagging of new technological development, cross-sectional technologies spanning over several sections above, and technical subjects covered by former US Patent Classification. For example: class Y02 – Climate change mitigation technology, Y10S -- subject matter covered by former USPC cross-reference, Y10T – Subject matter covered by former USPC

Please consult the CPC and IPC website for detailed scheme structure and definitions. Additionally, USPTO’s classification symbol lookup tool allows concordance search.

Strategic application:

Search for patents within a particular technology field to: 

• understand the position of an organization's technology portfolio 
• understand the emerging area of invention associated with the technology of interest
• understand a particular idea/technology's patentability 
• obtain insight into technology strategies, competitive advantages and IP SWOT