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The CPC classification — reading patent codes
10 min read · Patent Fundamentals
What is the CPC?
The Cooperative Patent Classification (CPC) is the global standard for organizing patent documents by technology. Jointly managed by the European Patent Office (EPO) and the United States Patent and Trademark Office (USPTO), it contains over 250,000 technology codes.
Every patent published worldwide receives at least one CPC code assigned by a trained patent examiner. This makes CPC the most reliable way to define a technology perimeter — far more consistent than keyword searches.
CPC HIERARCHY — 5 LEVELS
HSectionElectricity — the broadest level (9 sections: A-H, Y)H01ClassBasic electric elementsH01MSubclassProcesses or means for direct energy conversion (batteries, fuel cells)H01M 10/05GroupSecondary cells (rechargeable batteries)H01M 10/0525SubgroupLithium-ion batteries — the most specific levelWhy CPC codes matter more than keywords
A keyword search for "solid-state battery" misses patents titled "all-solid-state electrochemical cell" or "solid electrolyte energy storage device." CPC code H01M 10/0562 captures all of them regardless of language or vocabulary.
KEYWORDS
- ›Depend on applicant vocabulary
- ›Language-dependent (EN/FR/DE/CN/JP...)
- ›Inconsistent scope across searches
- ›Miss synonyms and variants
CPC CODES
- ›Assigned by trained examiners
- ›Language-independent classification
- ›Consistent scope globally
- ›Capture all variants of a technology
How to read a CPC code
Reading a CPC code is like reading a postal address — from broad to specific. Each level narrows the technology scope.
EXAMPLE: C12N 15/113 — CRISPR GENE EDITING
CChemistry; Metallurgy (Section)C12Biochemistry (Class)C12NMicroorganisms or enzymes (Subclass)15/113Modification of genetic material using recombinant DNA technology (Group)In Stratensight, the Source Coverage card in every analysis shows which CPC codes were used to define your technology perimeter. Understanding these codes helps you verify that the analysis covers the right scope.
KEY TAKEAWAYS
- ✓CPC organizes 250,000+ codes into a 5-level hierarchy: Section > Class > Subclass > Group > Subgroup.
- ✓CPC codes are assigned by examiners, making them more reliable than keyword-based searches.
- ✓Stratensight maps your technology query to CPC codes automatically — verify via the Source Coverage card.
TIME WINDOW — AUTOMATIC SELECTION BY MATURITY
Logic: More mature = shorter window (old patents = noise, not signal).
The user can choose manually: 1y · 3y · 5y · 10y · all.
SOURCE: ground_truth.json → query_engine.time_windows.auto_map
QUIZ DE VALIDATION
1. What does CPC stand for?
2. Why are CPC codes more reliable than keywords for technology mapping?
3. In the CPC code H01M 10/0525, what does the first letter 'H' represent?
4. How does Stratensight use CPC codes in its analysis pipeline?
5. What is the main risk of using only keywords instead of CPC codes for patent analysis?