What are Kind Codes?

Kind codes are 2-digit letter and number combinations which distinguish patent documents published by IP Offices.  Most patent offices issue more than one document for any particular patent, and so to distinguish these documents, which often keep the same serial number, a letter is added immediately after the number.  These codes are regularly given a numerical suffix, which indicates the number of times the document has been published.

In a very broad sense, the letter “A” is used to denote an unexamined application, “B” for an examined application, and “C” for a granted patent.  Although similar in different countries, the suffix letters do not have identical meanings and so it is wise to check the comprehensive kind code Excel spreadsheet supplied by WIPO.

AUnexamined Application
BExamined Application

The Japanese and European patent systems have a different procedure to US systems in terms of examination of their patent applications.  In Japan and Europe, an applicant has a certain time period after filing an application to decide whether to proceed to examination or not.  Conversely, in the US the application is automatically examined.  Therefore, this results in similar kind codes having different connotations in the different jurisdictions.