Kelvin Smith Library
A patent application is a request pending to be granted or issued a patent. A patent is the document at the end of the application process that has been granted a patent. The content of a patent application is different from the content of a patent.
To differentiate between patents and patent applications, one have to look at the letter following a patent number. The letter represents the kind codes used to distinguish the kind of patent document and the level of publication. Kind codes include a letter and, in many cases, a number.
Starting with January 2, 2001, all patent applications numbers end in A1, A2, or A9.
Starting with the same date, a granted or issued patent number ends in B1 or B2.
Check USPTO Kind Codes if the patent is dated before 2001 and to see all the other types of kind codes available:
Google Patents offers a fast way to find patents. However, a more comprehensive search has to be executed in USPTO databases.