The term of a utility patent is 20 years from the filing date of the earliest nonprovisional patent application in its chain of priority. A design patent term is 15 years from the date of grant. Those are the two numbers that matter most in 2026 — but whether your patent actually survives for its full term depends on several factors that are worth understanding before you file, and again before each maintenance fee comes due.
This guide covers everything you need to know: how the basic term is calculated for utility, design, and plant patents; how Patent Term Adjustment (PTA) can add days or years; how Patent Term Extension (PTE) applies in pharma and biotech; how terminal disclaimers can shorten a patent’s life; and how maintenance fees can end a patent prematurely if you’re not careful.
Term of a Utility Patent
Basic Calculation
Under 35 U.S.C. § 154, a utility patent expires 20 years after the filing date of the earliest U.S. nonprovisional application in its chain of priority. For example, if you file a nonprovisional application on January 15, 2025, your patent will expire on January 15, 2045 — assuming you pay all maintenance fees and no terminal disclaimer cuts it short.
Continuation and Divisional Patents
If your patent is part of a family — meaning it claims priority back to an earlier application — the 20-year clock runs from the filing date of that earliest nonprovisional application, not the filing date of the child patent. This is one of the most misunderstood aspects of patent term.
For example, if you file a parent nonprovisional application in 2018 and then file a continuation patent application in 2023 that claims priority back to the 2018 parent, the continuation patent expires in 2038 — not 2043. The continuation gets the benefit of the parent’s priority date for novelty purposes, but it also inherits the parent’s earlier expiration date.
Provisional Patent Applications
Filing a provisional patent application does not affect the patent term. The 20-year clock runs from the filing date of the nonprovisional application, not the provisional. If you file a provisional on March 1, 2024, and file your nonprovisional on March 1, 2025, your patent term runs from March 1, 2025.
This is a common misconception among inventors: they sometimes assume that claiming priority to a provisional “costs” them a year of patent term. It doesn’t. The provisional simply reserves your priority date for prior art purposes while giving you 12 months to develop the invention further.
Patent Term Adjustment (PTA)
The USPTO is required to examine patent applications on a specific timeline under 35 U.S.C. § 154(b). When the USPTO fails to meet its own deadlines, the resulting delays are added to the back end of your patent term as a Patent Term Adjustment. Think of it as the USPTO giving you back time it borrowed during prosecution.
There are three types of USPTO delays that generate PTA:
A-Delays — The USPTO fails to mail a first office action within 14 months of filing, or fails to respond to an applicant’s reply within 4 months.
B-Delays — The patent issues more than 3 years after the application filing date.
C-Delays — Delays caused by interference or derivation proceedings, secrecy orders, or appeals that the applicant wins.
PTA = (A + B + C delays) minus applicant-caused delays minus any overlap between delay types. Any time you take extensions of time during prosecution reduces your PTA dollar-for-dollar, so I generally recommend responding to office actions promptly. See my detailed guide on understanding Patent Term Adjustments for a worked example using the actual formula.
When your patent issues, you have 60 days to challenge the USPTO’s PTA calculation if you believe it is incorrect. After that window closes, the PTA printed on your patent is final.
Patent Term Extension (PTE) — Pharmaceutical and Biotech
For products subject to pre-market regulatory review — primarily pharmaceuticals, medical devices, food additives, and certain pesticides — 35 U.S.C. § 156 (the Hatch-Waxman Act) allows a patent term extension of up to 5 years to compensate for time spent awaiting FDA approval. The extended term generally cannot exceed 14 years from the date of FDA approval.
PTE is separate from PTA and applies to a narrow category of patents directly tied to the regulatory review period. If you’re in pharma or biotech, this is worth a dedicated conversation with your patent attorney early in the process.
Terminal Disclaimers
A terminal disclaimer is a document filed during prosecution in which the patent owner voluntarily gives up any patent term that extends beyond the expiration date of a related patent. Examiners require terminal disclaimers to overcome nonstatutory double patenting rejections — situations where two patents owned by the same party claim obvious variants of each other.
The practical effect: if you file a terminal disclaimer tying your continuation patent to a parent that expires in 2035, the continuation also expires in 2035 — even if it would otherwise have run until 2040. Always check the file history for any terminal disclaimers before drawing conclusions about a patent’s expiration date. I recommend doing this for every competitor patent you monitor.
Term of a Design Patent
A design patent expires 15 years from the date of grant. Unlike utility patents, the design patent term is not calculated from the filing date, and there are no maintenance fees. For design patent applications filed on or after May 13, 2015 (when the U.S. implemented the Hague Agreement), the term is 15 years. Applications filed before that date have a 14-year term.
Design patents also do not benefit from Patent Term Adjustment. What you see on the grant date is what you get.
Term of a Plant Patent
Plant patents follow the same 20-year-from-filing rule as utility patents under 35 U.S.C. § 163. They also have no maintenance fees, similar to design patents.
Maintenance Fees: Keeping Your Patent Alive
A utility patent does not automatically stay in force for its full 20-year term. You are required to pay three maintenance fees at the following intervals after the date of grant:
- 3.5 years after grant
- 7.5 years after grant
- 11.5 years after grant
If you miss a maintenance fee, your patent will expire prematurely. There is a 6-month grace period during which you can pay with a surcharge, but after that the patent lapses. The USPTO does allow reinstatement for unintentional lapses, but the process involves filing a petition and paying back fees — it is not automatic.
My recommendation: each time a maintenance fee comes due, step back and honestly assess whether the patent is still generating value. If the patented product is no longer generating revenue or deterring competitors, paying the fee may not make business sense. On the flip side, if competitors are actively selling products that your patent covers, letting it lapse is a costly mistake.
The Old 17-Year Rule (Historical Reference Only)
If you’ve come across references to a “17-year from issuance” patent term, that rule applied to patents issued before June 8, 1995, when the U.S. changed its law to comply with the GATT treaty. All patents governed by the 17-year rule have long since expired. For any patent filed after June 8, 1995, the 20-year-from-filing rule applies.
USPTO Patent Term Calculator
Because term calculations can get complicated — especially in family situations with multiple priority dates, PTAs, and terminal disclaimers — the USPTO publishes a free patent term calculator on its website. It walks you through the inputs and outputs the expected expiration date. It is a useful starting point, but it does not account for terminal disclaimers or unreported maintenance fee lapses, so always verify against the actual file history.
The Bottom Line
The 20-year utility patent term sounds simple, but the actual expiration date of any given patent depends on at least five variables: when the first nonprovisional was filed, whether any PTA was granted, whether a terminal disclaimer was filed, whether maintenance fees were paid, and — in pharma/biotech — whether a PTE was obtained. Before you conclude that a patent is or isn’t enforceable, check all five.
If you need help determining whether your patent — or a competitor’s — is still in force, I’m happy to take a look. You can also re-patent an expired patent? — short answer: no, but you can build a portfolio of improvement patents that extends your market protection well beyond the original term.
Should you have any questions, please feel free to contact me at 949-433-0900 or [email protected]