How to use the patent term expiration calculator
Knowing exactly when a patent runs out drives freedom-to-operate work, licensing talks and product planning. Enter the earliest filing date for the base expiration, add the issue date to see the maintenance fee schedule, and add any adjustment or extension days printed on the patent for the true end date.
The governing rule is 35 U.S.C. section 154(a)(2): a utility patent term ends 20 years from the earliest United States or PCT filing date to which the application claims priority. Enforceable rights begin only at issue, so the start and the end are measured from different events. Section 154(b) patent term adjustment adds days back for USPTO delay, and section 156 patent term extension restores time lost to federal regulatory review up to five years. Utility patents also require maintenance fees 3.5, 7.5 and 11.5 years after issue under 37 C.F.R. section 1.362, each with a six-month grace period. Design patents are different: section 173 gives them 15 years from grant with no maintenance fees.
Figures reflect September 2026. A terminal disclaimer, a failure to pay maintenance fees or a post-grant proceeding can all end a patent earlier than the calculated date, so confirm the current status in USPTO Patent Center.
This calculator is for reference only and is not legal advice. Consult a registered patent attorney or agent about your specific situation.
Frequently asked questions
From filing. Under 35 U.S.C. section 154(a)(2) a utility patent term ends 20 years from the earliest U.S. or PCT filing date it claims priority to, while enforceable rights begin only when the patent issues.
Patent term adjustment under section 154(b) adds days back for delays caused by the USPTO during prosecution. Patent term extension under section 156 restores time lost to federal regulatory review, up to five years. Both are printed on the issued patent or in USPTO records.
For utility patents they fall due 3.5, 7.5 and 11.5 years after issue, each with a six-month grace period at a surcharge. Missing them lets the patent expire early even though the 20-year term has not run.