How to search for patents


  • Keywords
    • identify keywords through background research
    • background questions
      • Purpose: What does the invention do?
      • Application: What is it used for?
      • Structure: What is the invention made of and what are its parts?
      • Function: How does it work?
      • Consumers: Who might benefit from using it?
  • Classification number
    • try to figure out what classification number is appropriate
    • Cooperative Patent Classification (CPC)
      • hierarchy of the classification number
        • Section (one letter A to H and also Y)
        • Class (two digits)
        • Subclass (one letter)
        • Group (one to three digits)
        • Main group and subgroups (at least two digits)
        • Example: A45B23/00
  • References
    • search through similar patents to see if you can find your patent
  • Boolean Operators
    • AND, OR, NOT
  • Truncation
    • common symbols - *, $, ?
  • Phrase searching
    • "..."


  • patent searching can be tricky
  • you probably have to use all of the search techniques and at least a couple of different search tools
  • search is iterative - you find something new, search with the new information, find something more and use that, and so on
  • 7 step patent search strategy guide (USPTO)
Content last reviewed: November 1, 2019