Receipt and Handling of Mail and Papers

Certificate of Mailing — 37 CFR 1.8 / MPEP 512 Allows using date of deposit with USPS as filing date for most USPTO papers. Applies to papers in existing applications only — NOT new applications, not international filings, not national stage entries. Also excludes: Board proceedings, interference/trial proceedings, and correspondence to PTAB. Certificate must be signed and must identify the paper. If mail is lost, must petition with evidence of deposit.

Priority Mail Express — 37 CFR 1.10 / MPEP 513 New applications CAN use Priority Mail Express deposit date as filing date. Must use USPS Priority Mail Express with date of deposit label. Date on label = filing date. Also applies to national stage entries. Does NOT apply to regular first-class mail.

Deadlines — Saturdays, Sundays, Federal Holidays — 37 CFR 1.7 If deadline falls on Saturday, Sunday, or federal holiday in DC, deadline automatically extends to next business day. Applies to USPTO regulatory deadlines only — not statutory bars. USPTO closures due to weather/emergency also trigger extension.

Office of Filing and Information Management — MPEP 501 All papers must be addressed to Director of USPTO. Papers addressed elsewhere risk not receiving official USPTO filing date. Electronic filing via Patent Center preferred — gets filing date of submission if received by midnight ET.

Time Periods — MPEP 505 Statutory periods set by statute — cannot be extended by petition (e.g., 12-month provisional deadline). Regulatory periods set by rule — can be extended by petition with fee under 37 CFR 1.136. Know the difference: statutory vs regulatory period extension rights.