How to Conduct a US Patent Search

Before filing a patent application, most intellectual property lawyers recommend that their clients authorize them to perform a patent search.

However, it’s not unusual for many clients, especially those who are extremely conscious of costs, to forego a search.

While this frequently is inadvisable, it’s by no means prohibited. There is no legal requirement that a patent search be performed before an application is filed.

Still, it can be useful to know before filing an application whether or not patent protection is likely to be available. Even more critically, it helps to know what scope of protection is likely available. For instance, is this truly a brand new, never-before-seen invention or is this a refinement of existing products?

If it’s the latter, then it’s helpful to be able to narrow down the valuable nugget of the improvement so that the claims can be directed to this subject matter.

What is a patent search, and how is one performed? Let Williams IP Law guide you through this complex subject.

What Is a Patent Search?

Sometimes called a patentability search, this is a search through existing patents and other documents that are available to the public. These patents and documents are referred to as “prior art.”

The purpose of the patent search is to find the prior art that comes the closest to your invention. Effectively, this is what an Examiner at the U.S. Patent and Trademark Office also does, looking for prior art that may be used to argue that your invention is obvious and not new when compared with the prior art.

While this type of search will not tell you whether or not your invention will infringe someone else’s patent, it can identify the closest prior art to help with a determination as to how patentable the invention is and which parts are unique when compared with the prior art.

The purpose of the patent search is to save the inventor time and money. After all, what’s the use of paying to have an application drafted, filed and examined if the invention has already been patented?

The cost of a patent search is far less expensive in comparison.

Can You Do Your Own Patent Search?

Some inventors decide to perform their own patent search to save some money. This may make it more affordable for them to proceed with the drafting and filing of the application.

If you’re interested in doing your own patent search, use these steps:

  1. Brainstorm descriptive terms
  2. Search CPC scheme at the USPTO website
  3. Review the classification definition
  4. Find issued patents using the appropriate CPC classification
  5. Review each patent
  6. Find published patent applications
  7. Consider broadening your search

Let’s take a closer look at each of these steps.


The first step involves writing a description of your invention. Try to be as specific as possible, and consider synonyms for any of the words that you might use to define or describe your invention.

Are there certain keywords or technical terms that describe your invention? It may be helpful to consult resources such as dictionaries and thesauruses to get ideas.

Searching CPC Schema

Now, it’s time to visit the website. Use the search text box at the top right corner of the screen.

In the search box, enter “CPC scheme” and one of the keywords that you brainstormed in the first step.

The USPTO follows CPC classification schema. When you type “CPC scheme” into the search box, it will return results that include entries on the Class-Subclass Scheme page.

You can run this search as many times as you like, searching for other keywords to find the classification titles that look most relevant to your invention.

An example class/subclass classification or identifier might look like “2/456.” The two corresponds to Class 2, which is Apparel while the 456 subclass refers to Body cover.

Review Classifications

Some of the classification titles in your search results will be underlined. If so, then this title is hyperlinked to a CPC Classification Definition. These definitions are useful when it comes to establishing the scope of the chosen classification. Accordingly, this helps to determine if you have found the most relevant classification.

Clicking on these hyperlinks always is worthwhile because they may provide further search suggestions or search notes.

Find Patents Using the CPC Classification

Head back to the Home page at the website, and click on the Find It Fast Quick links Patent window located just below the search text box.

This will bring up a link labeled PatFT under the Patents heading. Click on this link to go to the patent search page.

The CPC Classification that you found can be placed in the search menu under Term 1. For the Field, choose Current CPC Classification.

Click Search, and you’ll receive a list of issued patents. Click on the number or title of any listed patents to read the full text of the patent. Some will have an “Images” button that will give you a full PDF of the patent.

It’s wise to review at least the first page of all of the entries. If you find any that seem really similar to your invention, make note of them.

Review Selected Patents

Now it’s time to fully examine each patent that you made note of in your search. Pay particular attention to the drawings and claims to determine just how similar they are to your invention.

Find Patent Publications

Go back to the main page. Once again, click on the Quick Links window, but this time, select the AppFT under the Patents heading.

This takes you to a similar search screen, but now you are searching for published patent applications which have not issued as patents.

The search process is the same as far as entering in the CPC Classification number and reviewing for the most relevant results.

Broadening Your Search

It may be wise to use the PatFT and AppFT search systems to look for keywords as well. Additionally, some inventors decide to look for foreign patents using the Espacenet website. This could be especially important if you have hopes of patenting your invention in other countries.

Patent Searching Is Imperfect

No matter who conducts your patent search, it is critical to realize that no patent search is perfect. It is impossible to find absolutely every reference that might have some relevance, and there may be unpublished patent applications that are not available at the time of your search but that become available by the time your application is being examined.

In other words, a patentability search can provide guidance and insight, but it is in no way any kind of guarantee that you will get a patent for your invention.

Opt for a Professional Patent Search

Patent searching is complex, and it usually is advisable to have a professional conduct the search so that you get the broadest possible picture of the prior art before you go to the trouble and expense of filing a patent application.

Contact Williams IP Law today if you have more questions about patent searching or filing patent applications. Our experienced practitioners and staff can guide you through the process of pursuing patent protection.

Author: Jeff Williams

Jeff Williams is an experienced mechanical engineer and lawyer that consults closely with clients in a strait forward and clear manner.  He brings a particular set of strengths and unique perspectives to the firm.    
 Jeff received a B.S. in Mechanical Engineering from Arizona State University in 2005.  He was an engineer for a number of years at a number of large corporations before pursuing his law degree.  He graduated from Texas A&M University School of Law (formerly Texas Wesleyan University School of Law) with a J.D. in 2010.  By combining his education and prior work experience into the field of intellectual property law, Jeff has developed key skills to fully assist clients.