Meaning 4 of 5 · Patents
Cooperative Patent Classification
By Oliver Wakefield-Smith, Digital Signet. Updated July 2026.
In patent work, CPC is the Cooperative Patent Classification: a scheme for sorting patent documents by technology, run jointly by the European Patent Office and the United States Patent and Trademark Office CPC, official site. Nothing to do with advertising.
What it is and what it replaced
Patent offices classify every published document so examiners and searchers can find prior art by technology rather than by keyword. The CPC harmonised the EPO's and USPTO's previously separate schemes into one shared, far finer-grained system, managed jointly by the two offices CPC, official site.
How a CPC symbol is structured
A symbol narrows from a one-letter section to a precise subgroup. Decoding a real one:
Worked decode · G06N 20/00
Sections run A to H plus Y (cross-sectional tagging). Each level narrows the technology until a subgroup describes something as specific as a single technique.
Looking up a code
The full scheme and its definitions are browsable at the official CPC site. For searching by classification, use Espacenet (EPO) or Patent Public Search (USPTO); both let you combine CPC symbols with keywords, which is how professional prior-art searches are built.
Different CPC?
The advertising metric is at what is CPC. Also see the UN product classification, Driver CPC, or the full router.