Index Search

For the basics of this tutorial, we are going to research the computer mouse.

The second step involves looking up the terms you have generated through brainstorming in the Index to the U.S. Patent Classification. The index is an alphabetical list of subject headings referring to specific classes and subclasses of the classification system. For our invention we need to look up mouse.

  1. Visit 
  2. Screenshot of USPTO homepage.
  3. Hover over the Patents heading in the navigation bar across the top of the page and click on the link titled Patent Classification. This link takes you to the main Patent Classification page.
  4. Screenshot showing patent classification link.
  5. Under Patent Classification Resources, choose the link titled Classification Index, Patents, which will take you to the U.S. Patent Classification (USPC) Index.
  6. Screenshot showing link to patent classification index.
  7. Click on M for mouse on the Index in HTML row. 

    TIP: Instead of scrolling down to find "mouse" in the page, use your browser's find command. Go to Edit and select "Find in page..." (or use Ctrl+F on a PC or Command+F on a Mac). This will allow you to enter your word and jump quickly between instances of it on that page.
  8. Screenshot of U.S. Patent Classification System homepage.
  9. Under the Mouse heading you see that the subheading Computer Input and Display Control seems to describe your invention. We can rule out the other subheadings, such as "multicellular living organisms."

  10. Note: For your own patent search, the subheading match may be less clear. You may want to continue looking up words from your brainstorming list to better understand the classification system.
    Screenshot of patent classification subheading "mouse."
  11. Take a look at the numbers on the right side of the page. These are classification codes. They consist of a class and subclass. For computer mouse, the class is 345 and the subclass is 156. The plus sign next to our classification code is a reminder that when you perform the next step, examining the Manual of Classification, you will want to look at the subclasses located near your classification for other closely related classifications.

Screenshot of patent classification subheading "mouse" showing class and subclass numbers.