When a patent or application is published (example portion of page one of an issued patent illustrated below) you may see letters and numbers after the patent number (here B1).
These are called “kind codes” and mean the following:
- A1 - patent application publication
- A2 - patent application re-published
- A9 - patent application corrected and published
- B1 - Patent having no pre-grant publication
- B2 - Patent having a pre-grant publication
- C1, C2, C3 - Reexamination certificates
- E - Reissue patent
- F1, F2, F3 - Supplemental examination certificates
- H - Statutory Invention Registration (SIR)
- J1, J2, J3 - Post grant review certificates
- K1, K2, K3 - Inter partes review certificates
- O1, O2, O3 - Derivation certificates
- P1 - Plant patent application publication
- P2 - Plant patent having no pre-grant publication
- P3 - Plant patent having a pre-grant publication
- P4 - Plant patent application re-published
- P9 - Plant patent application corrected and published
- S - Design patent
This brief note is not legal advice and is for educational purposes only.
