How Long Does a Patent Last? Utility, Design, and Plant Patents Explained

Utility Patent Term: 20 Years From Filing

The standard term for a U.S. utility patent is 20 years from the filing date of the earliest U.S. non-provisional application to which the patent claims priority. This is set by 35 U.S.C. § 154.

A critical point that surprises many inventors: the 20-year clock starts at filing, not at issuance. Because utility patent applications typically take 2 to 3 years to work through the USPTO examination process, by the time a patent issues the effective enforcement window is often only 17 to 18 years. This is a meaningful reduction — and it underscores why filing a well-prepared application that minimizes unnecessary delays is important.

If you filed a provisional application before your non-provisional, the 20-year term still runs from the non-provisional filing date, not the provisional date. The provisional application itself does not start the patent term clock.

For patents that claim priority to an earlier-filed parent application through continuation or continuation-in-part applications, the 20-year term runs from the filing date of the earliest application in the chain whose disclosure supports the claims. Patent portfolio management — deciding when to file continuations and how to structure the priority chain — can significantly affect the effective life of a family of patents.

Design Patent Term: 15 Years From Grant

Design patents follow a different rule. For applications filed on or after May 13, 2015, the design patent term is 15 years from the date the patent is granted. For design applications filed before that date, the term was 14 years from grant.

The shift from 14 to 15 years brought U.S. design patent terms into alignment with the Hague Agreement, which governs international design registration. Unlike utility patents, design patent terms run from the grant date rather than the filing date — so there is no erosion of the term during examination. A design patent that takes 20 months to issue still provides a full 15-year protection window from that issuance date.

Design patents also have a significant financial advantage: no maintenance fees are required. Once issued, a design patent stays in force for its full 15-year term without any ongoing fee payments. For inventors and small companies managing IP costs, this makes design patents a relatively low-maintenance form of protection.

Plant Patent Term: 20 Years From Filing

Plant patents, which protect asexually reproduced distinct and new varieties of plants (such as cultivars propagated by cuttings, budding, or grafting rather than by seed), follow the same 20-year-from-filing rule as utility patents. Plant patents are less common than utility or design patents but are significant in agricultural sectors — a relevant consideration for inventors in North Dakota's agricultural economy.

The distinction between plant patents and plant variety protection certificates (issued by the USDA) is worth noting. Plant variety protection covers sexually reproduced plants (grown from seed) and is administered separately from the USPTO patent system. The two systems have different terms, fees, and scope of protection.

Maintenance Fees: Required for Utility Patents

Utility patents do not automatically remain in force for their full 20-year term. To keep a utility patent alive, the owner must pay maintenance fees at three intervals after the patent issues:

• 3.5 years after issuance: Due between 3 years and 3 years 6 months after the grant date
• 7.5 years after issuance: Due between 7 years and 7 years 6 months after the grant date
• 11.5 years after issuance: Due between 11 years and 11 years 6 months after the grant date

As of 2025, the maintenance fee amounts for a small entity are approximately $800 at 3.5 years, $1,800 at 7.5 years, and $3,700 at 11.5 years. Large entities pay double these amounts. The fees increase over time, reflecting the presumption that a commercially successful patent generates increasing revenue as it matures.

If a maintenance fee is not paid by the due date, the USPTO provides a 6-month grace period during which the fee can be paid with a surcharge. If the grace period also passes without payment, the patent expires and is unenforceable. There is a petition process to revive an unintentionally abandoned patent, but it is not guaranteed and involves additional fees and delays. Missing maintenance fee deadlines is one of the most preventable ways to lose valuable patent rights.

Design patents and plant patents do not require maintenance fees.

What Happens When a Patent Expires?

When a utility patent expires — whether at the end of its 20-year term or due to failure to pay maintenance fees — the invention enters the public domain. Anyone can freely make, use, sell, and import the previously patented technology without license or royalty. This is the intended bargain of the patent system: the inventor receives a time-limited monopoly in exchange for full public disclosure of the invention, after which the public gains unrestricted access.

Expired patents are frequently studied by competitors, follow-on innovators, and manufacturers looking for technology they can use freely. Many products that are now widely available as generics or commodities were once protected by utility patents.

Patent expiration does not affect other forms of intellectual property protection that may cover the same product. A trademark on a brand name, copyrights in software code or documentation, or trade secrets in manufacturing processes can survive and continue to provide competitive protection long after the patent expires. This is why a comprehensive IP strategy considers all available forms of protection, not just patents.

Calculating Your Patent's Expiration Date

For a utility patent, the calculation is straightforward: find the filing date of the earliest U.S. non-provisional application in the priority chain, and add 20 years. For example, a utility patent application filed March 1, 2020 would expire on March 1, 2040, assuming maintenance fees are paid and no adjustments apply.

The complication comes from patent term adjustments (PTA), which can extend the 20-year term to compensate for USPTO delays. Under 35 U.S.C. § 154(b), the USPTO is required to make examination timely. If the USPTO fails to act within certain deadlines during prosecution — such as failing to issue a first office action within 14 months of filing, or failing to issue a patent within 3 years of filing — the patentee earns PTA days that are added to the back end of the patent term. PTAs of several months to over a year are not uncommon for patents that experienced significant examination delays.

Conversely, applicant delays during prosecution can reduce the PTA. If the applicant takes longer than 3 months to respond to a USPTO action, the excess days are deducted from any accumulated PTA. Managing prosecution timelines efficiently preserves patent term.

The USPTO calculates PTA for each patent and prints the PTA on the face of the patent. If you believe the USPTO's PTA calculation is incorrect, you can petition for a correction — but petitions must be filed within deadlines, and this is specialized work best handled by a patent attorney.

Patent Term Extension for Pharmaceuticals

A separate provision — patent term extension under the Hatch-Waxman Act — allows pharmaceutical patent holders to extend a utility patent term to compensate for time lost to FDA regulatory review. The extension can be up to 5 years, with the total post-approval patent term capped at 14 years. This provision is specific to drug patents and human biological products subject to FDA approval and does not apply to general utility patents.

For inventors and businesses in non-pharmaceutical sectors, patent term extension is not available. The standard 20-year utility patent term, subject to PTA, applies.