What Is a Patent Number?

A patent number is an identifier assigned by a patent office and is used often in a patent search. The format depends on the issuing office, the type of patent, and when the patent was issued.

Patent numbers may contain a combination of several pieces of information:

  • The year the patent was issued
  • The number of the patent
  • One or more kind codes, which provide more information about the patent

For example:

  • In the United States, issued patents generally begin with "US." That is followed by the one-to-seven-digit patent number. The last part is a kind code. Each part is separated by a hyphen.
  • A U.S. Design patent number starts with a "D" or the letters "Des."
  • Some U.S. patent applications are published. A published patent application receives a publication number. This begins with U.S. That is followed by the publish year and patent number. The kind code is the last part.

Other patent offices include the:

  • European Patent Office (EPO)
  • Japan Patent Office (JPO)
  • World Intellectual Property Organization (WO or WIPO)
  • Australian Patent Office (APO)

Each patent office uses a different patent number format. Some patent offices reset the numbering each year while others don't. However, the use of year, patent number, and kind code is common.

Over time, a patent office may change the format of its patent number. That means you may notice a different patent number format depending on when a given patent was issued.

You can usually find relevant patent numbers on a commercial product or in the documentation that comes with it. Patent application or publication numbers are hard to find and may require some research.

Why Is a Patent Number Important?

A patent number indicates that a product or invention is protected by a patent. That means the patent holder can stop other people from using patented property. He or she can also sell or license the patent.

Patent numbers are also valuable to anyone doing patent research. With a patent number, you can look up the details of the patent.

What Information Can I Find With a Patent Number?

Once you have found the patent associated with the patent number, you can see all the information in the patent. This includes:

  • Inventor's name
  • Patent holder's name
  • Patent issue date
  • Patent title
  • Type of patent
    • Utility, Design, or Plant Patent
    • Patent Application Publication: Published patent application
    • Reissued Patent: Reissued with changes to a previous patent
    • Defensive Publication or Statutory Invention Registration: Documents that argue against issuing a patent
  • Current class number (CCL)
  • Term extension notice (if applicable)
  • Application number, date, and other related patents or applications
  • U.S. and international classification information
  • Cited references
  • Primary and assistant examiner names
  • Name of attorney or firm
  • Abstract summary
  • Drawings and/or designs
  • Specifications and claims

Patent formats vary by country. However, countries share common labeling using INID codes. That means even if you don't read the language, you can tell what field you're looking at.

How Do I Search for a Patent Number?

There are several ways to find a patent number.

PatFT contains full text records for patents issued from 1976 to now. It also contains images of older patents. However, you need to know the patent number or classification to search for them.

  1. To search this database, enter whatever information you have about the patent. This can include:
    • Patent holder's name
    • Inventor's name(s)
    • Keywords related to the invention
    • One Boolean operator, like AND, OR, or ANDNOT
  2. Define your search by selecting the kind of information you have entered.
  3. Select the year range you want to search.
  4. Click "Search."
  • PatFT Advanced Search
  1. Go to the same page as PatFT Quick Search. Choose "Advanced" at the top of the page. Advanced search allows you to use command line syntax. Keep in mind:
    • Advanced search terms are not case-sensitive. However, Boolean operators must be capitalized.
    • Certain words, like "various" and "invention" are excluded as search terms because they are too common.
    • Use the field codes listed below the search box to define your search.
    • Searches have a 256-character limit. To find the character length of your search, right-click on the results hit list and choose "Properties."
  2. Narrow the year range of your search. Otherwise, it will default to the full database.
  3. Click "Search."

How Do I Search for a Patent Using a Patent Number?

Once you know the patent number, go to a patent database:

From there, you can enter the patent number to find either the abstract or the full patent record.

Get familiar with the USPTO website. Here you can find drawings and full texts of patents that were once only available in Washington D.C. and certain large libraries. From the homepage:

  1. Click "Patents."
  2. Click "eSearch Patents" under "Services."
  3. Click "Patent Number Search."
  4. Enter the patent number, including "D" if you're looking for a design patent. Do not include commas.
  5. Click the blue patent number in the lower left corner.
  6. Click "Images."

You can also search for international patents. First, decide which country's patents you want to search. Then figure out how that country formats its patent numbers. (For example, Japanese patent numbers start with "JP.")

Search international patents with a global patent search tool:

If you need help with a patent number, you can post your question or concern 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.