What are the kind codes for U.S. patent publications?

U.S. patent publications use specific kind codes to indicate the type and status of a document. According to MPEP 901.04(a):

• A1: Patent Application Publication
• A2: Republished Patent Application Publication
• A9: Corrected Patent Application Publication
• B1: Utility Patent
• B2: Utility Patent (issued after reexamination)
• C1, C2, C3, etc.: Reexamination Certificate
• E1: Reissue Patent
• H1: Statutory Invention Registration (SIR)
• P1: Plant Patent
• S1: Design Patent

These codes help identify the specific type and status of a U.S. patent document at a glance.

To learn more:

• kind codes
• U.S. patents
• patent publications
• document types