Patent Kind Codes: USPTO A1, B1, and B2 Meanings

Patent kind codes are letter-and-number suffixes that identify the type and publication stage of a patent document. If a citation ends in A1, B1, or B2, the code helps you determine which version of the record you are viewing.

Key Takeaways

• In current USPTO records, A1 generally identifies a published patent application, while B1 and B2 identify issued patents.
• A U.S. B2 patent was preceded by a published application. A B1 patent was not.
• A kind code describes a document publication, not the patent's current validity, ownership, enforceability, or expiration status.
• The same code can mean something different at the USPTO, WIPO, or European Patent Office.
• Kind codes differ from patent types, patent classifications, legal status codes, and INID bibliographic codes.
• Corrected and republished documents may carry a new kind code, so confirm that you are reading the intended version.

What Are Patent Kind Codes?

A patent kind code is placed after a patent document's publication number. It distinguishes an application publication, granted patent, correction, republication, or another document issued by a patent authority. WIPO Standard ST.16 provides recommendations for using these codes, but each authority defines the codes it assigns.

A standard patent document identifier contains three parts:

1. Country or publishing-authority code: US identifies the United States, EP identifies the European Patent Office, and WO is used for publications of international applications under the Patent Cooperation Treaty.
2. Publication number: This identifies the particular published document. A U.S. application publication commonly includes a year, while an issued U.S. patent uses a patent number.
3. Kind code: A suffix such as A1, B1, or B2 identifies the document kind and publication stage.

For example, US 2003/1234567 A1 follows the format for a U.S. patent application publication. US 7,654,321 B1 follows the format for an issued U.S. patent that did not have an earlier pre-grant publication. The kind code usually appears beside the publication number on the document's front page and in database search results.

Do not read the letter or number in isolation. A B patent document is often a grant, but the precise meaning depends on the publishing authority and publication date. The USPTO changed its principal kind-code system on January 2, 2001, so older U.S. documents require separate interpretation.

USPTO Kind Codes Quick Reference

The following table covers the USPTO kind codes most readers encounter when reviewing applications, utility patents, plant patents, design patents, reissues, and corrected publications. The relationship column shows when the document normally follows or replaces another publication.

Other USPTO codes identify reexamination, supplemental examination, post-grant review, inter partes review, and derivation certificates. When one appears, check the USPTO definition and the proceeding record instead of assuming it has the same effect as a standard grant.

A1 Patent Meaning Versus B2 Patent Meaning

In a current U.S. citation, an A1 patent code actually identifies a published application, not an issued patent. The publication makes the application's disclosure available to the public, but the claims shown in that A1 document may change during examination.

A B2 patent is an issued utility patent whose application was previously published. The basic document sequence is:

1. An application is published and receives an A1 kind code.
2. Examination continues, and the applicant may amend or cancel claims.
3. If the USPTO grants the application, the issued patent receives a B2 kind code.

A B1 patent is also an issued utility patent, but it comes from an application that was not previously published as a U.S. pre-grant application publication. Thus, B1 versus B2 describes the publication history before grant, not two different levels of patent rights.

The application publication and grant are related records, but their numbers and claims may differ. A database's patent-family or related-application information can help connect the A1 publication to the later B2 grant. When comparing them, read the claims in the B2 document rather than assuming the A1 claims survived unchanged. Applicants responding to an examiner should follow the applicable USPTO patent amendment format, and those amendments can affect the claims that ultimately issue.

This distinction also explains why searching only an A1 publication can produce an incomplete answer. The application may have issued, been abandoned, continued in another application, or generated additional related records after the A1 document was published.

Why a Patent Kind Code Does Not Prove Legal Status

A kind code identifies what the patent office published. It does not establish that a patent remains active, that every claim is enforceable, or that the named owner still owns it. Even a B1 or B2 grant may require further review before you rely on it for a business or legal decision.

Check at least five separate issues:

• Current status: Determine whether the patent is active, expired, or affected by later proceedings. An expired or fee-related patent status requires more analysis than reading the suffix.
• Claims: Review the issued claims and any later certificates that changed them.
• Patent family: Identify continuations, divisionals, foreign counterparts, and other related filings.
• Ownership: Examine recorded transfers using the USPTO Patent Assignment Database, while recognizing that the record may not answer every ownership question.
• Proceedings and corrections: Look for reexamination certificates, post-grant proceedings, reissues, disclaimers, or corrected publications.

A database status label can be useful, but it should not replace review of the official record. Dates, maintenance-fee information, prosecution events, assignments, and court decisions may all matter. A kind code alone also cannot tell you whether your product falls within an issued claim.

If a cited document may affect freedom to operate, ownership, or enforcement, you can post your legal need on UpCounsel's marketplace. A patent attorney can review the patent family, prosecution history, current status, claims, assignments, and relevant jurisdictional records. Responses typically arrive within a day, helping you move from decoding a suffix to evaluating the document's practical legal effect.

Patent Kind Codes by Country and Publishing Authority

WIPO Standard ST.16 promotes a consistent format, but it does not make every authority's definitions identical. Always interpret the suffix under the rules of the office that published the document.

This comparison shows why B2 patent meaning changes by authority. In a U.S. record, B2 indicates a grant that followed a pre-grant publication. In an EP record, B2 identifies a patent specification amended after opposition. Likewise, WO A1 provides information about publication with an international search report, not the grant of a worldwide patent.

Official definitions are available through the USPTO kind-code resource, WIPO's PCT kind-code reference, and the EPO kind-code guide. Check the relevant authority when comparing national, regional, and PCT records.

Kind Codes Versus Patent Types, Classifications, and INID Codes

A patent kind code answers, "What document version did this authority publish?" It does not describe the invention's technical field or substitute for the patent category. Several other codes and labels appear on the same front page.

• Patent types: U.S. patents generally include utility, design, and plant patents. A provisional application is often included in informal lists of four types of patent filings, but it is an application, not an issued patent. If you are seeking functional protection, the filing process is explained in this guide to filing a utility patent application.
• Patent classification: International Patent Classification and Cooperative Patent Classification symbols organize documents by technical subject matter. Researchers use them to find inventions in related fields. They do not indicate whether a document is an application or grant.
• INID codes: These standardized numbers identify bibliographic data fields on patent documents. They help you locate items such as publication data, filing information, priority information, classifications, applicants, inventors, and titles.
• Application and publication numbers: These identify filings and published documents. They are not interchangeable with kind codes.
• Legal status information: Register events, maintenance-fee records, certificates, assignments, and other official entries provide information that the publication suffix does not.

For example, an A1 publication may display an international patent classification symbol that identifies the invention's subject matter and INID numbers that label front-page fields. A1 still serves a separate function: it identifies the published document as an application publication under the relevant authority's system.

Keeping these systems separate makes searches more accurate. Use the kind code to select the document version, classification codes to broaden or narrow technical searching, INID codes to read the front page, and official register information to investigate status and ownership.

How to Look Up a Code and Confirm the Correct Version

Start with the complete identifier shown in the citation. Include the publishing-authority code, publication number, and kind code when available. Then follow these steps:

1. Open the official record. Search the USPTO for U.S. documents, WIPO PATENTSCOPE for WO publications, or the European Patent Register for EP records.
2. Match the full number. Confirm that the country or authority code, publication number, and suffix match your citation.
3. Inspect the front page. Verify the publication date, applicants, inventors, title, priority data, and kind code.
4. Find related publications. Look for an earlier A1 application, a later B1 or B2 grant, foreign counterparts, continuations, or other members of the patent family.
5. Check for corrected versions. A2, A9, B8, B9, P4, or P9 may signal a republication or correction in a U.S. record. Read any correction notice and confirm which pages or fields changed.
6. Review the official register. Check prosecution events, certificates, assignments, maintenance information, and other status records relevant to your purpose.

Do not assume the first search result is the final or legally relevant version. A database may rank an application publication above its later patent, or it may group family members from several jurisdictions. Select the specific publication you need and compare its claims and front-page data with related records.

Corrections to ownership records present a separate issue from corrected patent publications. If an assignment contains inaccurate information, the process may involve a corrective assignment filed with the USPTO. That ownership correction does not necessarily change the patent document's kind code.

Frequently Asked Questions

What Does B2 Mean at the End of a Patent Number?

On a modern U.S. patent, B2 means the patent issued from an application that had already been published before grant. The suffix describes that publication history. It does not show whether maintenance fees are current, whether ownership changed, or whether later administrative or court proceedings affected the claims.

What Are the Four Types of Patents?

There are three principal types of U.S. patents: utility, design, and plant patents. Lists describing four types often add provisional applications, but a provisional application is not a patent and is not examined as one. It can establish an early U.S. filing date if the applicant satisfies the applicable requirements and follows with a timely nonprovisional filing.

What Does B2 Mean on a Patent From Outside the United States?

B2 must be interpreted under the publishing authority's rules. For example, an EP B2 document is a European patent specification amended after opposition, which differs from the U.S. meaning. Use the country or authority code at the beginning of the citation before deciding what the suffix signifies.

Where Can I Find INID Codes?

INID codes appear on the front page of many patent documents, usually as numbers in parentheses beside bibliographic fields. The issuing authority's documentation and WIPO standards explain those fields. They help you identify information such as publication, filing, priority, classification, applicant, inventor, and title data without relying on the document's language.

What Is the Difference Between an A1 and B2 Patent?

For U.S. documents, A1 is the public application-stage record and B2 is the later grant associated with a previously published application. When conducting a claim analysis, use the B2 claims as the issued set and review the prosecution record for amendments, disclaimers, certificates, or later proceedings that may affect your conclusions.