How to Conduct a Patent Search

How to Conduct a Patent Search

Last Edited September 11, 2023 by Garenne Bigby in Business

Eureka! The light bulb has gone off. Or perhaps an idea has been simmering in your mind for quite a while. Whatever the situation, you are ready with an incredible idea for an invention. Perhaps this will be the next special invention, the next big thing, or what will make you attain your financial goals. For those creative and talented individuals who are looking to invent, or simply for the entrepreneurs who wish to cut costs and do their own patent search—the following guidelines will show you the way. How might one obtain a patent, you may be wondering? It can be a challenging process since we live in an age of inventions and advancements. How can you be sure your idea has not yet been patented? Has someone already beaten you to the punch? How can you be sure your invention is not already patented?

A patent search is critically important as the first step in your application process; especially making sure it is done thoroughly, in order to ensure the originality of your product. Patents can also be quite expensive. Adding up all of the costs for the application, the lawyer to back you with legalese, the technical drawing, the end cost can literally be thousands. Learning how to do a patent search can save you a lot of money in the end.

What is a Patent Search?

This is principally a search where you look for similar ideas that are mentioned in either academic or technical literature. It is referred to by the government as “prior art search” Searches for a patent must be conducted and findings submitted with your application and given to the USPTO. Any inventor has the obligation, legally binding, to give any relevant information, which they know of about a similar invention. If it is discovered that you had the knowledge and did not submit any information to the USPTO, the patent may not be granted or you may be charged legal costs for an infringement. This is considered inequitable conduct or even fraud to the patent office.  

If you do a prior search and the USPTO accepts the distinguishing invention, your application and acceptance of the patent hold a legal validity, which is very challenging for others to contest. This means you will be eligible to hold a patent and have legal rights to your invention.   


What makes your invention unique? You may be astonished to find how many “fresh” ideas are already patented, though you’ve never seen anything even remotely resembling it on a store shelf or in a catalog. Even before spending time or money to file for a patent, it is important to conduct a patent search. Doing so will also help you gain valuable insight into refining your idea and gathering information about your potential competition.

Think of specific terms and phrases someone could use in describing a product such as yours—based on its purpose, what it’s made of, and its use. Be specific but also creative. How do you envision your invention being used? How does it look and how does it function? What materials is it made of? Think of how searching from different perspectives is possible. Think of how an artistic person or perhaps an engineer would describe its looks. This will help your search to be not only on point but also very fruitful in finding what you are looking for. It increases your chances of finding a similar product if one does indeed exist.

Use a Trusted Searching Tool

  • United States Patent and Trademark Office - When you do your own search and seek to find relevant patents, you need to learn some strategies and about some free tools that are readily available. When you do your own searching, take a look first at the USPTO search page. There is a lot of free information, and the site is very easy to use. They have a very beneficial help section on the patent website in order to help educate the users on the best way to perform a search for patents.  
  • Free Patents Online - Free Patents Online is easy to access and has many patent illustrations. They provide actual PDF copies of a document, which allows freedom of access to images. This is an extremely useful tool as it allows for ease of research and access to information at your fingertips. It is also faster than USPTO. Using both of these sites can be helpful, as USPO has a better search engine. Everything at FPO is linked, so it is easy to jump back and forth to compare what each search engine offers.
  • Google Patent Search - Google Patent Search is very rapid but has some real limitations. There are limited fields that can be searched, compared to either USPTO of FPO. It is probably best to use GPS initially in order to cast an extensive search of patents. When you start searching for specific terms, try switching to one of the useful tools above. A negative to this site is that sometimes the most recent patents do not have availability on the frontline. However, one benefit is that the Google database has patents issued even back to the first patent—US Patent #1. It is a much broader range than either the FPS or USPTO.  There may not be everything you need on this site, but if you use the Google database to check older references, it is a useful tool indeed.
  • International Searching - Another possibility is using sites such as Patent Monk or Espacenet, which is operated by the European Patent Office. A point to consider, however, in looking at international patents, the best technique may be to call in a professional search agency or perhaps a patent attorney. A professional can cost you megabucks, but will end up providing helpful and valuable assistance in the end, especially in the international domain.  
  • Patent and Trademark Resource Center - You can also contact a PTRC (Patent and Trademark Resource Center) near you. The workers will not be able to offer you legal advice, but they can certainly provide you access to helpful patent search resources. These may include local patent attorneys, assistance on how to make a patent search from many years ago, classes on using intellectual property, and much more. There are those are quick to help you find the resources you need to patent an idea.

How to Conduct a Patent Search

To begin a successful search, you must use the classification search. The system is helpful, but remember that it is the USPTO that classifies as it sees fit. A broad search is necessary in the beginning in order to help familiarize yourself as to how an inventor or patent attorney may characterize a certain invention, its features, and any scientific principles and concepts behind it. It is important to begin your search with a broad idea of all descriptions possible.  

1. Determine Patent Type:

First, try to figure out the type of patent you are looking to file. There are three classifications for this:

  • Utility – Any invention that has a practical application.  An example is a metal alloy, or a car that flies, perhaps a method to generate electricity, a new way to heat using geothermal energy, et cetera.

  • Design – This is for products with an ornamental purpose strictly. Examples are beverage containers, a cookie cutter, a lampshade, et cetera.

  • Plants – This is for any new plant species that can reproduce on their own. Examples being a hybrid Rose such as the Smooth Angel, the Snow White zantedeschia, or a new type of tomato plant.

2. Identify Keywords

Write down the terms that you think will describe your invention with the following:

  • What is it made of – materials, substance, parts

  • What does it do or achieve – what is the purpose of your invention

  • What is it used for – how does it work, why is it useful  

3. Identify Relating Classes and Subclasses

Using a search website, click on the first letter of your keyword. Each keyword is given a class number representing a general category and a subclass number representing a specific invention: such as 2/209 for earmuffs—2 being for “apparel” and 209 given for “ear”. Scan these lists and write down all classes and subclasses that apply to your keywords.

One trick that helps improve searching is to begin with the Advanced Search Page in order to search specific fields. As an example, if you are trying to find a patent that includes containers that are insulated and carry beverages.  

  • The first thing to do would be to pick terms or phrases that you are looking for within the description of the issued patents. This example would have you search something like—SPEC/”insulating beverage container”. This search had been conducted in the past (June 30, 2015) and the results that were returned were a list of about 27 patents that were issued from 1976 using that particular phrase.  

  • Sometimes the list contains thousands of patents. For instance, if you use the search SPEC/”thermos”, you may find hundreds of patents using this word's specification. There were no less than 1144 patents in the US that have “thermos” for the specification, and this is only searching back to 1976.  

  • One way to narrow down the search is to be as precise as possible. Using SPEC/”thermos” and SPEC/”beverage” would narrow it down to 241 patents at least.  

  • The key is to start broadly and then narrow your search down to the most relevant specifications.

One major difficulty with doing your own search is using keywords with precision. An inventor may use them individually or simply, but very often it is beneficial, and the searches are more successful when keywords are used in combinations. It is also good when a variety of them are searched, as different inventions, similar to yours, may be patented using various keywords.

  • Finding the proper combination of keywords is really important as it causes the doors to open unto possibilities. Using the best keyword combination helps you have a competent search in order to find specific inventions that may be similar in design or function to yours.

  • Once you receive manageable results, be sure to read all of the patents to see which are relevant.  Try to remember using various search terms that cover all possible descriptions of an invention. This is important, especially considering the variety of inventions, possible terms, and possible descriptions of different patents.

  • When you read the patents, identify those that are related in order to keep track of any of the numbers that identify the US classification and relate to a type of invention that you are searching.  

  • After finding several US classifications relating to your invention, be sure to return to your Advanced Search Page in order to perform a classification search.

Using the example given above, there is a classification of 206/545 that seems relevant to an area of insulated containers used for beverages. It would seem then that any patent within a classification such as this are highly relevant. Returning to the Advance Search Page, you could enter “CCL/206/545” and this would search for all patents classified by 206/545. You can also add a classification in order to narrow your search. As an example, using “CCL/206/545 in addition to SPEC/beverage” would narrow the search to 55 US patents that were issued since the year 1976.  

4. Check the CPC

The Cooperative Patent Classification is r the United States Patent Classification (USPC). Luckily, these categories are linked, so it makes searching easier.  

  • Using the USPTO website, seek the USPC classification system
  • Enter the class and subclass of the classification symbol

  • Select “Statistical Mapping” from the “Select Content” field.  This gives related suggestions for CPC classes as well as subclasses.

  • Search the classes/subclasses the same way as when you searched US patents.

  • Review patents in CPC subclass by going back to PatFT.

5. Take Your Time

Certainly, being familiar with any of the intricacies of searching for a US patent by yourself takes time. Even using the Advanced Search Page, there are a number of ways in which you are able to begin to tackle a search. If you invent regularly, it is definitely worthwhile to spend ample time to become acquainted with searching techniques. If you are already familiar with the classification systems and the advanced searching techniques, you have a possibility of still missing what you are looking to find in doing your search. Many times an inventor will make the advised preliminary search and not find anything at all. This is not uncommon.  

6. Employ a Professional

It makes sense to do a personal search in the beginning, especially to cut down on expenses. However, it is very common for an inventor to make a patent search and have no results when a professional searcher may find things quite easily. If you’re new to this, there is a good chance that you will have less comprehensive results on your own than perhaps an experienced searcher would find. There is no comparison to a professional helping you search. Searching can be compared to trying to find a needle as they say in a haystack. A professional who searches for a living is very familiar with the classification system or even a patent attorney. This is important to realize, and though it may cost you many thousands of dollars, it could end up being the help you need in the end and save you many more thousands in the long run.  

Decide if You Should Seek a Patent

Finally, after all of these steps, decide if your application will pass inspection. If there are any USPC or CPC similar to yours, your invention application will most likely be rejected, and it will be time to start anew. If nothing seems similar, then you are free to apply and may very well have an invention that is patent-worthy.  

Maybe you have a state-of-the-art idea that is truly earth-shattering, fresh, new, and amazing. Perhaps you’ve discovered how to solve an age-old problem or discovered a new technology. Ideas, of course, cannot be patented, but if you flesh it out to where your idea is truly an invention, you will want to start the process to make your patent application. Remember a critical first step is to be sure your idea is unique. Then, conduct your patent search.

Using the techniques and tips above, you can easily do a very good search right from your home. This will save you much cost in the long run. Of course, a professional search will always be the best choice if you have the funding behind you. Try a professional searcher or patent attorney. If this isn’t possible, there are many free tools available to help you in your search. In the end, be specific, be thorough, and if you don’t find anything that resembles your invention, go for the glory and submit an application!  

Garenne Bigby
Author: Garenne BigbyWebsite:
Founder of DYNO Mapper and Former Advisory Committee Representative at the W3C.

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