How is the priority period calculated for U.S. nonprovisional applications?

The priority period for U.S. nonprovisional applications is calculated as follows:

• The first day (filing date of the foreign application) is not counted.
• The period ends on the same date of the following year (or six months later for design applications).
• If the last day falls on a weekend or federal holiday, the period extends to the next business day.

The MPEP provides an example: If an application was filed in Canada on January 3, 1983, the U.S. nonprovisional application may be filed on January 3, 1984. (MPEP 213.03)

This calculation method is consistent with Article 4C(2) of the Paris Convention, which specifies that the day of filing is not counted in this period.

To learn more:

• Priority period calculation
• Filing date
• Paris Convention