On some patent numbers I see an "A1" / "A2" / "B2" etc. suffix after the actual patent number

e.g. "USxxxxxxxxx B2" or "WOxxxxxxxx A1" etc.

What do these suffixes mean? Is there a key somewhere that lists what they mean?

1 Answer 1


These are kind codes. They are effectively version numbers for published versions of the patent application. Every country has their own set of kind codes, but typically an A code (such as A1) represents a patent application, and a B code (such as B2) represents a granted patent.

The background behind this system is provided in WIPO's standard ST.16. WIPO also maintains a list of the actual codes used by each country.

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