How are patent application publications numbered and identified?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

Patent application publications have a unique numbering system and identification method. According to MPEP 901.04(a):

Each year the numbering of published patent applications will begin again with the new four-digit year and the number 0000001, so the number of a patent application publication must include an associated year.

For example, a patent application publication might be identified as:

• US 2003/1234567 A1

In this case, ‘2003’ indicates the year of publication, ‘1234567’ is the sequential number, and ‘A1’ is the kind code for a first publication of a patent application. This system ensures that each patent application publication has a unique identifier that includes both the year and a sequential number.