What happens to the expiration date of a provisional patent application if it falls on a weekend or holiday?

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.

If the 12-month pendency period of a provisional patent application expires on a weekend or federal holiday, it is extended to the next business day. According to MPEP 710.05:

“The period of pendency of a provisional application will be extended to the next succeeding secular or business day which is not a Saturday, Sunday, or a federal holiday, if the day that is twelve months after the filing date of the provisional application under 35 U.S.C. 111(b) and 37 CFR 1.53(c) falls on Saturday, Sunday, or a federal holiday within the District of Columbia.”

This extension is provided by 35 U.S.C. 119(e)(3) and ensures that applicants have a full business day to file a non-provisional application or take other necessary actions.