On January 2, 2001, the United States Patent and Trademark Office (USPTO) began printing the World Intellectual property Organization (WIPO) Standard ST.16 code on each of its published patent documents. WIPO Standard ST.16 codes (kind codes) include a letter, and in many cases a number, used to distinguish the kind of patent document (e.g., publication of an application for a utility patent (patent application publication), patent, plant patent application publication, plant patent, or design patent) and the level of publication (e.g., first publication, second publication, or corrected publication). Detailed information on Standard ST.16 and the use of kind codes by patent offices throughout the world is available on the WIPO web site.

In addition, some kind codes assigned to existing USPTO patent documents were changed due to the upcoming introduction of USPTO patent application publications resulting from the American Inventors Protection Act of 1999 (AIPA). The first patent application publications are expected to be published in Mid-March 2001. Thereafter, patent application publications will be published weekly on Thursday. Additional information on the AIPA, including the rules pertaining to publication of patent applications, is posted on the USPTO web site.

The tables below give a summary of the kind codes which are no longer being used on certain published patent documents as well as a summary of the kind codes which will be used on published patent documents after January 2, 2001. It is recommended that USPTO documents be identified by the following three elements: 1) the two-character country code (US for United States of America); 2) the patent or publication number; and 3) the WIPO ST.16 kind code. For example, "US 7,654,321 B1" for US. Patent No. 7,654,321 where there was no previously published patent application publication, and "US 2003/1234567 A1" for U.S. Patent Application Publication No. 2003/1234567, published in 2003. Each year the numbering of published patent applications will begin again with the new four digit year and the number 0000001, so the number of a patent application publication must include an associated year.

Summary of USPTO Kind Codes No Longer Used As of January 2, 2001*

WIPO ST.16 Kind Codes	Kind of Document	Comments
A	Patent	Kind codes replaced by B1 or B2
P	Plant Patent	Kind codes replaced by P2 or P3
B1, B2, B3 ...	Re-examination Certificate	Kind codes replaced by C1, C2, C3 ...

* See the table below for the new uses for codes B1 and B2 beginning January 2, 2001

Summary of USPTO Kind Codes Used on Documents Published Beginning January 2, 2001

WIPO ST.16 Kind Codes	Kind of Document	Comments
A1	Patent Application Publication	Pre-grant publication available March 2001
A2	Patent Application Publication (Republication)	Pre-grant publication available March 2001
A9	Patent Application Publication (Corrected Publication)	Pre-grant publication available March 2001
B1	Patent	No previously published pre-grant publication
B2	Patent	Having a previously published pre-grant publication and available March 2001
C1, C2, C3 ...	Re-examination Certificate	Previously used codes B1 and B2 are now used for granted Patents
E	Reissue Patent	No change
H	Statutory Invention Registration	No change
P1	Plant Patent Application Publication	Pre-grant publication available March 2001
P2	Plant Patent	No previously published pre-grant publication
P3	Plant Patent	Having a previously published pre-grant publication and available March 2001
P4	Plant Patent Application Publication	Pre-grant publication available after March 2001
P9	Plant Patent Application Publication (Corrected Publication)	Pre-grant publication available after March 201
S	Design Patent	No change

Amended Reasons

Amended Reason	Date Amended
	18 Oct 2023
Publishing for testing	06 Jun 2023