When is a preamble considered limiting in patent claims?

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.

A preamble is considered limiting when it gives life, meaning, and vitality to the claim or if it recites essential structure or steps. According to MPEP 2111.02:

“If the claim preamble, when read in the context of the entire claim, recites limitations of the claim, or, if the claim preamble is ‘necessary to give life, meaning, and vitality’ to the claim, then the claim preamble should be construed as if in the balance of the claim.”

This principle is illustrated in cases like Pitney Bowes, Inc. v. Hewlett-Packard Co. and Jansen v. Rexall Sundown, Inc., where the courts found the preambles to be limiting because they gave essential meaning to the claims.