What types of errors qualify for a Certificate of Correction?

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.

Certificates of Correction are typically issued for significant errors that affect the understanding or interpretation of the patent. According to MPEP 1480:

“In order to expedite all proper requests, a certificate of correction should be requested only for errors of consequence. Instead of a request for a certificate of correction, letters making errors of record should be utilized whenever possible. Thus, where errors are of a minor typographical nature, or are readily apparent to one skilled in the art, a letter making the error(s) of record can be submitted in lieu of a request for a certificate of correction.”

The USPTO has discretion in determining whether to issue a Certificate of Correction. Minor typographical errors or mistakes that are obvious to those skilled in the art may not warrant a formal correction. In such cases, a letter documenting the error for the record may be more appropriate.