US Patent Maintenance Fees
All utility patents that issue from applications filed on or after December 12, 1980 are subject to the payment of maintenance fees which must be paid to maintain the patent in force. These fees are due at 3 1/2, 7 1/2 and 11 1/2 years from the date the patent is granted and can be paid without a surcharge during the ―window-period‖ which is the six-month period preceding each due date, e.g., three years to three years and six months. (See fee schedule for a list of maintenance fees.) In submitting maintenance fees and any necessary surcharges, identification of the patents for which maintenance fees are being paid must include the patent number, and the application number of the U.S. application for the patent on which the maintenance fee is being paid. If the payment includes identification of only the patent number, the Office may apply payment to the patent identified by patent number in the payment or the Office may return the payment. (See 37, Code of Federal Regulations, section 1.366(c).)
Failure to pay the current maintenance fee on time may result in expiration of the patent. A six-month grace period is provided when the maintenance fee may be paid with a surcharge. The grace period is the six-month period immediately following the due date. The USPTO does not mail notices to patent owners that maintenance fees are due. If, however, the maintenance fee is not paid on time, efforts are made to remind the responsible party that the maintenance fee may be paid during the grace period with a surcharge. If the maintenance fee is not paid on time and the maintenance fee and surcharge are not paid during the grace period, the patent expires on the date the grace period ends.