NIPSIA-LOGO National Intellectual Property Society of Iranian Americans

Basics of Patent Search

This short article is meant to provide a quick guide for people intersted in doing simple search for patents or published patent applications. Searching and comparing your invention with the prior art (e.g., things that already exist as a patent or patent application anywhere in the world, or as a product or literature description anywhere in the world) helps you make a better decision as to whether your invention is new or not.

The USPTO provides an online guide and tutorial to help people search for patents, as well as a web interface to search for patent and patent applications. Here Patent refers to an issued patent, while Application refers to a published patent application that has not been issued into a patent yet. Patent applications generally get published about 1.5 years from their initial filings at the USPTO (actually about 1.5 years from their prority date). There are several numbers associated with patent and patent applications that are often used to uniquely identify them:

  • Application Serial Number is a number in form of 99/999,999 that is assigned to an application for a (utlilty) patent when the application is first filed at the USPTO.
  • Published Application Number (or Document Number) is a number in form 20120000001 which is assigned to an application when it is published (e.g., 1.5 year after its filing) and becomes accessible to public (with its most significant 4 digits signfying the year of publication). But just because an application gets published does not mean that it will get issued to a patent.
  • Patent Number is a number in form of 7,654,321 which is assigned to a patent application once the patent is finally issued by the USPTO. Patents become enforcible only after they are issued, but not while they are pending as applications. It typically tkes several years between filing an application for patent and the time the patent gets issued (if it does).

At the USPTO's web interface, you may search the patents by their Patent Number or search for patent applicatiopns by their Publication Number. However, you can also search based on keywords (and their combinations) and where they may appear in a patent or an application and other attributes. The USPTO's advance search for patent and patent applications includes examples of search syntax and field codes. Please note that the issued patents and pending applications are listed/searched separately.

You can do the search based on the Boolean search and the tags provided, as described at:

For a list of the tags and fields, please refer to:

For general search help, go to:

To view full page images, in addition to text, see:

Alternatively, you can go to a USPTO library/search room, e.g. at the USPTO (Madison Building), located 600 Dulany Street Alexandria, VA 22314, to use the search engine and computers available to public for free, which employ very powerful search engine for patents and applications. You only pay for the pages printed, or you can store the search results.

USPTO has libraries all over the US, and they are opening more satellite offices all over the US in the next few years.

You can also use Google to search for patents, where you can look at the text and image, or download/print the PDF file.