Google Patent Search

Use Google Patent Search as an initial starting point for investigating patents--it covers up to those published in the last few months. Google Patents provides patents in PDF format. For a more comprehensive search, go to the USPTO or other patent offices, such as European Patents.


US Patent & Trademark Office

Complete listing of U.S. patents from 1790 to the present. The results include the fulltext of patents, as well as TIFF images. You can also search for patent applications since March 2001.

Query [Help]



Patents from 1790 through 1975 are searchable only by Issue Date, Patent Number, and Current US Classification.
When searching for specific numbers in the Patent Number field, patent numbers must be seven characters in length, excluding commas, which are optional.

How to search for patents

  • For an overview of how to conduct a U.S patent search, watch the 35-minute presentation from the USPTO. (Needs Adobe Presenter)
  • For an introduction to patent searching, visit the Patent and Trademark Depository (University of Texas at Austin)

By Subject

  1. Go to the USPTO database and select Quick Search.  Enter keywords in the search box.
  2. Find a patent that is close to what you're looking for.
  3. Note the U.S. Classification Number / Subclass for the patent.
  4. Do a search of that Class / Subclass in the USPTO database to find more patents on that subject.

OR ...

    Go to the Index to the U.S. Patent Classification System and search for common terms or keywords.
    Use the Class / Subclass numbers you found to check the Manual of U.S. Patent Classification to see if they are on target.
    Search by Class / Subclass numbers in the USPTO database.

By Patent Number

  1. Go to the USPTO database.
  2. Select Patent Number Search or Publication Number Search.

You can use the same method of searching in other patent databases on the web.

NOTE:  In order to perform an exhaustive search, additional methods must be used such as international patent documents and the review of non-patent literature.  That is why it is recommended that you contact a registered attorney or agent.  For a listing of registered patent attorneys, search the USPTO listing.