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Most patent bar date questions follow the same steps: count months from the date, add any extension bought, then move a weekend or federal holiday to the next business day. Enter dates to check your working.
Moved past: 2026-05-30 (Saturday), 2026-05-31 (Sunday) (35 U.S.C. 21(b); 37 CFR 1.7).
The 12-month priority year or provisional period, the 6-month design priority period, or the AIA one-year grace period.
A period set in months ends on the same day of the month as the mailing date, or on the last day of the month if that day does not exist (MPEP 710.01(a)). Extensions under 37 CFR 1.136(a) add whole months, up to five, but a reply can never be later than six months from the action (35 U.S.C. 133). A last day that falls on a Saturday, Sunday or federal holiday within the District of Columbia moves to the next business day (35 U.S.C. 21(b); 37 CFR 1.7). The same weekend rule applies to the 12-month priority year (MPEP 213.03) and the AIA grace period (MPEP 2153.01(a)).
Not modelled: Inauguration Day in the District of Columbia, unscheduled USPTO closures, periods that cannot be extended (for example the issue fee), and the different rules for reply briefs.
Go deeper for the exam: Patent bar cheat sheet.
Go to the same day of the month three months after the mailing date, or the last day of that month if the day does not exist. Add any extension bought, then move a weekend or federal holiday to the next business day (MPEP 710.01(a); 37 CFR 1.7).
Six months from the mailing date of the action, the statutory maximum under 35 U.S.C. 133.
For study and general guidance only, not legal advice. Figures checked 12 Oct 2026 against MPEP 710, 37 CFR 1.7 and 5 U.S.C. 6103. Rules change; confirm with the source before relying on a result.
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