What Is Patent Number Search?

A patent number search is when you search for a specific patent using its assigned number. To do this type of search you will first need to know the patent number. You can usually find this on a commercial product or its packaging. Utility patents have numbers that are in the millions. Design patents have numbers in the hundreds of thousands and start with the letter D or the letters Des.

Before investing in any patent application it is important to seek the counsel of a patent attorney and conduct a prior art search. This should include an investigation of known references through a patent number search to ensure that there are no possible blocking patents.

Sometimes inventors come up with a product that has already been patented. By doing a patent number search, you will better understand the scope of protection that is available to your invention. It will also help you to better understand where to file your patent applications and whether you will need to take measures to prevent possible infringement of existing patents.

The information you find by doing a prior art search and a patent number search could also help as you begin drafting your patent application.

What Is a Patent Application Number Search?

A patent application number search is when you are searching for a published patent application. Many patent applications are not published and therefore cannot be searched. You may want to do this if there is a product that is similar to yours in some way and you want to see what they wrote into their application.

To conduct a patent application number search, you need to know the publication number. The first four numbers of the publication number are the year the patent application was published.  Publication numbers are not usually placed on a product, so you will have to search to find the application number. If you can't find it by searching, you can contact the owner of the application for the publication number.

What Is Included in a Patent Number?

Patent numbers vary depending on the year that it was granted, the type of patent that was given, and the country where it is patented. The most common type of patent number comes from the World Intellectual Property Organization (WIPO) Standard ST.16 codes. This is the most recognized code among patent number search databases.

Usually, the WIPO Standard ST.16 codes include a letter followed by a number, then the level of publication (for example, first publication, second publication, or corrected publication).

Most patent number searches will identify U.S. Patent and Trademark Office documents using these three elements:

  • The two-character country code 
  • The patent or publication number
  • The WIPO ST.16 kind code

How to Do a Patent Number Search

Once you find the patent number for the patent that you want to search for, you can then search for it for free using one of two online patent databases. 

  • USPTO Patent Number Search
  • Google Patents

Using the PatFT Quick Search

1. Go to the US Patent Full-Text and Image Database (PatFT)

  • The PatFT holds full-text patents issued from 1976 to the present.
  • Older patents exist in the database as PDF images only. You can only search for pre-1976 patents if you have the patent number or know the official classification scheme.

2. Input all of the information you have about the patent you want to search for.

  • You can search US patents issued from 1976 to the present using any information that you have. You can also search for several patents that are related. For example, you could use the search function to find all of the patents that have been issued to Bill Gates.
  • Consider brainstorming some words that describe the invention. If you aren't looking for a specific invention, these can help you find related inventions that have received patents.

3. Enter your term in the "Query" blank.

  • If you want to use more than one search term you can use the drop-down menu to add connecting words like "and" or "or."
  • In the quick search, you can only search using two search terms and one connector word.
  • If you know the patent number, type it directly into the query box. Commas aren't required.

4. Define the fields of your search. 

  • After you enter the keywords, use the drop-down menu to tell the search engine the location of the term within the patent. If you don't know or you don't specify, the database will search all fields.

6. Limit the years on your search.

  • If you do not specify which years you want to search, it will search the entire full-text database covering patents issued from 1976 to present. The more you ask the database to search, the longer it will take and the more results you will have to sift through.

7. Click the "Search" button. 

  • The database will then display a list of all of the patents that matched your search terms. You can always refine your search to narrow it or you can click reset and start over.

8. Click on the patent number. 

  • If you see the patent that you want to look at, click on the blue patent number in the lower left corner of the page.

9. Click on Images.

  • Once you click on the images you'll be on page one of the patent. You can navigate through the pages of the patent using the tools on the left side of the page. Invention patents are usually at least two pages long. Design patents are generally just one page long.  
  • You can easily download, look at, and print the images of any patent before 1976. With broadband Internet, you can view and print the images of a ten-page patent in fewer than two minutes. 
  • Everything is free on the USPTO's website unless you want the patents to be sent to you by mail.

Using the PatFT Advanced Search

1. Go to the PatFT Advanced Search page.

  • You can navigate to the advanced search page by clicking the Advanced button at the top of the page.

2. Enter your search in the "Query" box.

  • The advanced search page lets you use command line search words to make your search more complex.
  • Advanced searches aren't case-sensitive.
  • If you are adding Boolean commands like AND or OR, those should be capitalized.
  • Make sure you know what the USPTO's stop words are. If you include any of these in your search they will not appear in your search results because they are used too often to be useful in a patent search.
  • You can search for a specific word in a particular field by using the field codes listed in the table underneath the search box.
  • Searches can't exceed 256 characters when they are fully expanded. You can find out how long your search length is by right clicking on the hit-list link once you've completed your search. Select properties once you right-click and you will see how long your search is.

3. Enter the year you want to search.

  • You can search by specific years or over a range of years.
  • The advanced search page gives you a drop-down menu so you can limit the years.

4. Click the "Search" button

  • The database will give you a list of all of the patents that matched your criteria. 
  • If you aren't happy with the results you can refine your search or reset it to start over.

Using Google Patents  

1. Go to the Google Patents Page.

2. Enter a patent number.

  • Once you hit search you will be able to access the PDF version of the patent that you want to view. 
  • Google allows you to search several different fields.
  • Be aware that the information isn't perfect because it was scanned from patent documents. The text recognition is not 100 percent correct. For example, an uppercase M is sometimes mistaken as the letter combination IVI. You may have to search specific information a few different ways before you find what you are looking for.

3. Use Google Patent Advanced Search, if you want to search by:

  • Patent number
  • Patent title
  • Inventor name
  • Assignee name
  • U.S. Classification
  • International Classification
  • Patent status (if it is issued yet or not)
  • Patent type
  • Issue date
  • Filing date

Doing a Search for International Patents

1. Figure out which country issued the patent that you are looking for.

  • Every country has its own database for patents and different ways of formatting the patent numbers.
  • For example, a Japanese patent begins with the letters "JP." 
  • Some countries re-use patent numbers every year while others continue to issue numbers in the same sequence as the previous years.

2. Use an international patent database.

  • Find a site where you can search international patents such as the World Intellectual Property Organization's PatentScope. This database has over 2 million published international patent applications and it also has really simple search capabilities that allow you to put limits on certain fields.

3. Find the Cooperative Patent Classification (CPC) or the International Patent Classification (IPC).

  • If you don't know the patent number, you can usually search for international patents using their CPC or IPC numbers.
  • You can easily find the relevant CPC number on the USPTO's website. If you want to know the CPC classification for sunglasses, search for "CPC Scheme sunglasses."

4. Search on national and regional patent databases.

  • Many countries have their patent databases in English so that you can find similar patents in that country.
  • The European Patent Office has a free database called Espacenet where you can find patents from all over the world, including the U.S. You can only view the images as PDFs. 

Fee-Based Patent Searching Databases

If you aren't finding what you are looking for on the free online databases, you may want to explore some of the fee-based patent searching databases to deepen your patent search.

  • LexisNexis Academic
  • SciFinder Scholar (specifically for Chemical Abstracts and chemical patents)
  • Delphion
  • Thomson-Reuters Patent Web
  • PatentMax
  • PatBase 

Offline Patent Searches

If you don't feel comfortable doing searches online or you need to search for patents issued before 1976, offline patent searches are the best option for you.

You can go to special libraries called Patent and Trademark Depository Libraries that are well-stocked with patent materials. These libraries also have experienced reference librarians who can help guide you through your patent search. Every state has at least one of these libraries.

Tool Patent Searches

Tool patent searches are relatively simple if it has been entered into DATAMP. DATAMP is the Directory of American Tool and Machinery Patents.

You can search for patents by inventor, manufacturer, or issue date. When you find the patent you are searching for, the links on DATAMP will take you to the U.S. Patent Office website for specific patent information.

How to Do a Chemical Patents Search

The Chemical Abstracts Service (CAS) indexes chemical patents from roughly 25 countries and patent organizations. If you are searching for a chemical patent, the first place you should start is Scifinder.

1. Obtain access to SciFinder Scholar.

2. Go to Explore References.

3. To search by patent number, assignee name or inventor name, select Patent. Then enter the information that you have. 

4. If you want to search by subject, select Research Topic. You should then limit the document type to Patent.

5. Once you hit Search, you will be given a list of results that match your criteria.

Searching For Plant Patents

If you are searching for plant patents, your patent number search is slightly different.

When you apply for a plant patent, you need to submit full-color drawings or illustrations of the plant. While utility patents allow you to patent more than one aspect of an invention, only one patent is allowed to be issued for a single plant patent and it will apply to the entire plant.

Protection for a plant patent is for 20 years. It gives the inventors the right to prevent others from reproducing, selling, or using the plant. Plan patents cover distinct and new varieties of asexually reproduced plants, except for tuber propagated plants or plants found in an uncultivated state.

In order to patent a plant, it needs to be distinct from other plants. It has to have one more characteristic that distinguishes it from other plants in habit, method, ease of reproduction, the color of the flowers, stems, leaves, or flavor.

Protection is limited to a plant in its "ordinary meaning", which basically means that protection is only offered to plants that have a set of characteristics determined by their single, genetic makeup or genotype, which can be duplicated through asexual reproduction but can not be made or manufactured.

Sports, mutants, hybrids, and transformed plants are comprehended. While natural plant mutants may have occurred naturally, they need to have been found in a cultivated area. Algae and macro fungi are classified as plants. Bacteria are not.

When you search for a plant patent number you be aware of the following:

  • Plant patents always begin with PP.
  • PP is always followed by up to 5 numbers.
  • Plant patents classifications are determined first by type of plant they are, then by characteristics such as habit, and then additionally by further sub-classifications like the color.
  • If you already know the plant patent number, you can search for it in the same way as other patents on the USPTO website or Google Patents.

Accessing Plant Patent Photographs

  • All plant patents include photos of the plant, a description of how the plant was made, and references to patents that are related to this plant.
  • Each patent includes a description of how the plant was propagated, color photographs showing detailed views of the plant and its fruit, blossoms, etc., as well as references to related patents.

What to Know Before Doing a Patent Number Search

  • Any patents issued in 1976 and after are completely searchable. 
  • Patents were issued before 1976 are can only be searched by issue date, patent number, or patent classification.
  • Patents issued in or after 1920 can also be searched by the inventor. 
  • Patents issued during or after 1848 were almost always issued on a Tuesday. This can help you choose specific dates to narrow your search.
  • If you know the month and year that the patent was issued, but not the exact day, you can enter $ in the day field and fill in the month and year to get all patents issued during that month. For example, entering 199505$ will return results for any patent issued in May 1995.
  • There are about 490 patent classifications. It is best to look up the patent classification for the type of patent you are searching for. This will help you to narrow your results.
  • Searching the USPTO patent database using keywords will likely not return the results that you want. For example, if you wanted to find the patent for a Rubik's Cube, searching the database for that would not bring up the intended invention which is titled Spatial logical toy.
  • Patent applications are in their own database called AppFT (Applications Full Text). This field has the name of the person or company who owned the patent at the time of filing.
  • If you are searching for the patent assignee by name and it is an individual, you should format your query as: last name-first name-initial.  
  • If the assignee is a company, and you're not sure of the exact name, you can use a portion of the name. If it doesn't come up on the first try, you may need to search variations of the company name. 

Frequently Asked Questions

  • What should I do if my patent number search doesn't yield any results?

If your patent number search is unsuccessful, it is possible that the USPTO has chosen not to make that specific patent available to the public. It is also possible that the patent was issued, then withdrawn. 

If you need help with a patent number search, you can post your legal need on UpCounsel's marketplace. UpCounsel accepts only the top 5 percent of lawyers to its site. Lawyers on UpCounsel come from law schools such as Harvard Law and Yale Law and average 14 years of legal experience, including work with or on behalf of companies like Google, Stripe, and Twilio.