37 CFR § 1.362 - Time for payment of maintenance fees.
(a) Maintenance fees as set forth in §§ 1.20 (e) through (g) are required to be paid in all patents based on applications filed on or after December 12, 1980, except as noted in paragraph (b) of this section, to maintain a patent in force beyond 4, 8 and 12 years after the date of grant.
(b) Maintenance fees are not required for any plant patents or for any design patents.
(c) The application filing dates for purposes of payment of maintenance fees are as follows:
(1) For an application not claiming benefit of an earlier application, the actual United States filing date of the application.
(2) For an application claiming benefit of an earlier foreign application under 35 U.S.C. 119, the United States filing date of the application.
(3) For a continuing (continuation, division, continuation-in-part) application claiming the benefit of a prior patent application under 35 U.S.C. 120, the actual United States filing date of the continuing application.
(4) For a reissue application, including a continuing reissue application claiming the benefit of a reissue application under 35 U.S.C. 120, United States filing date of the original non-reissue application on which the patent reissued is based.
(5) For an international application which has entered the United States as a Designated Office under 35 U.S.C. 371, the international filing date granted under Article 11(1) of the Patent Cooperation Treaty which is considered to be the United States filing date under 35 U.S.C. 363.
(d) Maintenance fees may be paid in patents without surcharge during the periods extending respectively from:
(1) 3 years through 3 years and 6 months after grant for the first maintenance fee,
(2) 7 years through 7 years and 6 months after grant for the second maintenance fee, and
(3) 11 years through 11 years and 6 months after grant for the third maintenance fee.
(e) Maintenance fees may be paid with the surcharge set forth in § 1.20(h) during the respective grace periods after:
(1) 3 years and 6 months and through the day of the 4th anniversary of the grant for the first maintenance fee.
(2) 7 years and 6 months and through the day of the 8th anniversary of the grant for the second maintenance fee, and
(3) 11 years and 6 months and through the day of the 12th anniversary of the grant for the third maintenance fee.
(f) If the last day for paying a maintenance fee without surcharge set forth in paragraph (d) of this section, or the last day for paying a maintenance fee with surcharge set forth in paragraph (e) of this section, falls on a Saturday, Sunday, or a federal holiday within the District of Columbia, the maintenance fee and any necessary surcharge may be paid under paragraph (d) or paragraph (e) respectively on the next succeeding day which is not a Saturday, Sunday, or federal holiday.
(g) Unless the maintenance fee and any applicable surcharge is paid within the time periods set forth in paragraphs (d), (e) or (f) of this section, the patent will expire as of the end of the grace period set forth in paragraph (e) of this section. A patent which expires for the failure to pay the maintenance fee will expire at the end of the same date (anniversary date) the patent was granted in the 4th, 8th, or 12th year after grant.
(h) The periods specified in §§ 1.362 (d) and (e) with respect to a reissue application, including a continuing reissue application thereof, are counted from the date of grant of the original non-reissue application on which the reissued patent is based.