A U.S. utility patent is good for 20 years from its filing date, a design patent for 15 years from its grant date, and a plant patent for 20 years from its filing date. Those are the statutory terms, and they answer the question on paper. In practice, how long a patent actually stays in force depends on whether maintenance fees get paid on time, whether the USPTO or the FDA caused delays, and whether the patent holder filed a terminal disclaimer that ties its expiration to an earlier patent.
Term by Patent Type
The United States issues three kinds of patents, each with its own duration.
- Utility patent. Covers new and useful processes, machines, articles of manufacture, and compositions of matter. Term: 20 years from the filing date of the non-provisional application.1Office of the Law Revision Counsel. 35 USC 154 Contents and Term of Patent; Provisional Rights
- Design patent. Protects a product’s ornamental appearance rather than how it works. Term: 15 years from the grant date.2Office of the Law Revision Counsel. 35 USC 173 Term of Design Patent
- Plant patent. Covers a new plant variety that has been asexually reproduced. Term: 20 years from filing, because the general patent provisions apply.3Office of the Law Revision Counsel. 35 USC 161 Patents for Plants
Utility patents are by far the most common, and most of the complications below apply to them.
When the Clock Starts
For utility and plant patents, the 20-year clock starts the day you file the non-provisional application, not the day the patent is granted. If your application claims priority to an earlier related application, such as a continuation or divisional, the term runs from the earliest filing date in that chain.1Office of the Law Revision Counsel. 35 USC 154 Contents and Term of Patent; Provisional Rights Years spent going back and forth with the USPTO during examination eat into the effective life of the patent, because the clock is already ticking before the patent issues.
Design patents are the exception. Their 15-year term starts on the grant date, so the length of examination does not reduce it.2Office of the Law Revision Counsel. 35 USC 173 Term of Design Patent
Provisional Applications
Filing a provisional patent application locks in a priority date without starting the 20-year term. You have 12 months to file a corresponding non-provisional application, and only that non-provisional filing starts the clock.4United States Patent and Trademark Office. Provisional Application for Patent This effectively adds a year of protection at the front end. Miss the 12-month window and the provisional expires by operation of law, though the USPTO allows a petition to restore the benefit if you file within 14 months and the delay was unintentional.
International (PCT) Applications
If you file through the Patent Cooperation Treaty and later enter the U.S. national stage, the 20 years run from the international filing date, not from national stage entry.5United States Patent and Trademark Office. The Differences Between a National Application Filed Under 35 USC 111(a) and a National Stage Application Submitted Under 35 USC 371 Because the international phase can take up to 30 months before national entry, a PCT route can meaningfully shorten the effective U.S. protection period.
Maintenance Fees Can Cut It Short
A utility patent does not automatically stay in force for the full 20 years. The patent holder has to pay maintenance fees to the USPTO three times after the grant, or the patent lapses. Design and plant patents have no maintenance fee requirement and remain in force for their full term once granted.6United States Patent and Trademark Office. Patent Maintenance Fees Overview
Under the fee schedule effective March 1, 2026, large-entity maintenance fees are:7United States Patent and Trademark Office. USPTO Fee Schedule
- 3.5 years after grant: $2,150
- 7.5 years after grant: $4,040
- 11.5 years after grant: $8,280
That is $14,470 over the life of one patent at large-entity rates. Small entities (qualifying independent inventors, small businesses, and nonprofits) pay 60% of the standard fee, and micro entities, who must also meet a gross income limit of $251,190 or less, pay just 20%.8United States Patent and Trademark Office. Micro Entity Status At micro entity rates, that first $2,150 fee drops to $430.
Grace Periods and Reinstatement
Each maintenance fee can be paid without a surcharge during a six-month window before its deadline. Miss the deadline and the USPTO gives you another six months to pay, but you owe a surcharge on top: $540 for large entities, $216 for small, $108 for micro.9United States Patent and Trademark Office. Maintain Your Patent The absolute last day to pay the first maintenance fee and keep the patent alive is four years after the grant date.
If the grace period passes and the patent lapses, reinstatement is still possible by petition. You pay the overdue fee, a petition fee, and file a statement that the delay was unintentional.10eCFR. 37 CFR 1.378 – Acceptance of Delayed Payment of Maintenance Fee in Expired Patent to Reinstate Patent The petition fee at large-entity rates is $2,260 for a delay of two years or less, or $3,000 for a longer delay.7United States Patent and Trademark Office. USPTO Fee Schedule The USPTO can demand more evidence if it questions whether the delay was really unintentional, and reinstatement is not guaranteed. Third parties who started using the invention during the lapse may also have intervening rights that limit what the patent holder can do about it. This is a last resort, not a planning tool.
When the Term Can Be Extended
Patent Term Adjustment
Patent Term Adjustment (PTA) adds days to a utility patent’s term to compensate for USPTO delays during examination. The number of days is calculated automatically and appears on the face of the patent.
PTA is triggered when the USPTO fails to meet specific processing deadlines, including issuing a first office action within 14 months of filing, responding to an applicant’s reply within four months, or granting a patent within three years of filing.1Office of the Law Revision Counsel. 35 USC 154 Contents and Term of Patent; Provisional Rights For each day the office runs past those benchmarks, a day is added to the term. Days come back off for applicant-caused delay, most commonly when the applicant takes more than three months to respond to an office action.11eCFR. 37 CFR 1.704 – Reduction of Period of Adjustment of Patent Term The number on the patent is the net.
Patent Term Extension for Regulated Products
Products that need lengthy regulatory approval before they can be sold, most commonly pharmaceuticals and medical devices, can lose years of patent life sitting in FDA review. Patent Term Extension (PTE) restores some of that time, but unlike PTA it requires a separate application to the USPTO.
The extension equals the time spent in regulatory review after the patent issued, with two caps. The extension itself cannot exceed five years, and the total remaining patent term after FDA approval plus the extension cannot exceed 14 years from the approval date.12Office of the Law Revision Counsel. 35 USC 156 Extension of Patent Term Only half of the testing phase counts toward the extension, and periods where the applicant did not act with due diligence are subtracted. PTE is available only for the first regulatory approval of a product, and only one patent per product can receive it.
When the Term Can Be Cut Short by Choice
A terminal disclaimer is a voluntary surrender of part of a patent’s term, usually filed to overcome a double patenting rejection when a newer application claims something too similar to an earlier patent owned by the same applicant.13United States Patent and Trademark Office. Definition of Double Patenting By filing the disclaimer, the applicant agrees the newer patent will expire on the same date as the earlier one and that both patents must stay commonly owned to remain enforceable.14United States Patent and Trademark Office. 1490 Disclaimers If the earlier patent was filed several years before the newer one, the newer patent’s effective term can shrink considerably. When you look up a patent’s actual expiration date, checking for a terminal disclaimer is a step that gets missed often.
What Expiration Means
Once a patent’s term ends, whether at the natural expiration date or early because of missed maintenance fees, the invention enters the public domain. Anyone can make, use, or sell it without permission or payment. There is no renewal process and no way to re-patent the same invention.
A Note on Pre-1995 Patents
Before June 8, 1995, U.S. patents lasted 17 years from the grant date rather than 20 years from filing. Under a transitional rule, any patent in force on that date or resulting from an application filed before it receives the longer of the two calculations.15United States Patent and Trademark Office. 2701 Patent Term Every patent from that era has long since expired, so the rule matters only for freedom-to-operate research on older inventions.