To tell if a patent is expired, look it up in the USPTO’s Patent Center using its patent number, read the status code on the application data page, and confirm that maintenance fees have been paid. Then compare today’s date against the patent’s calculated expiration, which depends on the patent type, the filing or grant date, and any adjustments printed on the face of the patent. The status code answers the question most of the time. The calculation catches the cases where it doesn’t.
Start With Patent Center
Patent Center is the USPTO’s public portal for prosecution history and current status. Search by patent number, application number, PCT number, or publication number.1United States Patent and Trademark Office. Patent Center – Search No account is needed to view public documents. The application data page shows filing date, issue date, patent type, and current status, and the file history holds the maintenance fee record, any terminal disclaimer, and the Patent Term Adjustment figure.
If you don’t have a patent number, use Patent Public Search first. It accepts inventor, assignee, and applicant names, which Patent Center does not.2United States Patent and Trademark Office. Patent Public Search Basic Once you identify the right patent, switch to Patent Center for status.
Reading the Status Code
Patent Center assigns each patent a status code. “Patented Case” means the patent is currently in force. “Patent Expired Due to NonPayment of Maintenance Fees” means the owner missed a fee and the six-month grace period lapsed. Other codes indicate the patent reached the end of its natural term or was abandoned during prosecution.
The code is a strong signal, not a final answer. A patent shown as “Patented Case” today can still be past its calculated expiration if the record hasn’t caught up, and a patent shown as expired for nonpayment can be revived. The full check is below.
Why Not Google Patents
Google Patents is good for reading patent documents and poor for confirming legal status. Its database lags patent office publications by weeks to months, and Google does not guarantee complete coverage of the offices it indexes. A patent that Google shows as active may have expired for a missed maintenance fee some time ago. For any decision that turns on current enforceability, use the USPTO directly.
Calculate the Base Expiration Date
The base term depends on the type of patent, and the clock starts in a different place for each.
Utility patents last 20 years from the earliest non-provisional U.S. application filing date.3United States Patent and Trademark Office. Managing a Patent The filing date, not the grant date, controls. A patent that took five years to issue used up five years of its term before the owner ever received it. For a utility patent that entered the U.S. through the Patent Cooperation Treaty, the 20 years run from the international PCT filing date.
Design patents filed on or after May 13, 2015, last 15 years from the grant date.4United States Patent and Trademark Office. MPEP 1505 – Term of Design Patent Design patents filed before that date last 14 years from grant.
Plant patents last 20 years from the application filing date, the same measurement as utility patents.5United States Patent and Trademark Office. General Information About 35 USC 161 Plant Patents
The Pre-June 8, 1995 Wrinkle
The 20-year-from-filing rule came in with the Uruguay Round Agreements Act on June 8, 1995. Patents in force on that date or issuing from applications filed before it get the longer of two terms: 20 years from filing, or 17 years from grant.6Office of the Law Revision Counsel. 35 US Code 154 – Contents and Term of Patent; Provisional Rights If you’re checking a patent issued in the early to mid-1990s, calculate both and use whichever date is later.
Adjustments That Extend the Term
Two things can push the expiration date past the base calculation.
Patent Term Adjustment
When the USPTO takes too long during examination, the law adds days to the patent’s term to make up for the delay.6Office of the Law Revision Counsel. 35 US Code 154 – Contents and Term of Patent; Provisional Rights The total Patent Term Adjustment is printed on the face of the patent and appears in Patent Center.7United States Patent and Trademark Office. MPEP – Patent Term Adjustment Determination A patent with 200 days of PTA expires 200 days after the base 20-year mark. Some patents carry PTA measured in years. Skip this step and your expiration date will be wrong.
Patent Term Extension for Regulated Products
Drugs, medical devices, food additives, and color additives sit in regulatory review before they can be sold, and that review eats into the patent term. Federal law allows a one-time Patent Term Extension to recover part of the lost time.8Office of the Law Revision Counsel. 35 US Code 156 – Extension of Patent Term The extension cannot exceed five years, the total exclusivity after FDA approval plus extension cannot exceed 14 years, and only one patent per product approval qualifies.
For a pharmaceutical patent, this is where the standard calculation breaks. A drug patent that would have expired in 2024 by its filing date could still be in force in 2029 with an extension. The USPTO publishes a list of extended patents,9United States Patent and Trademark Office. Patent Terms Extended Under 35 USC 156 and the FDA’s Orange Book lists patent expiration dates for approved human drug products.
Adjustments That Shorten the Term
Terminal Disclaimers
When an owner holds two closely related patents, the USPTO may require a terminal disclaimer on the later one so both expire together.10United States Patent and Trademark Office. MPEP 1490 – Disclaimers The disclaimed patent expires with the reference patent, and it also becomes unenforceable if the two patents end up in different hands. Terminal disclaimers appear in the file history. When one exists, identify the reference patent and use its expiration date.
Missed Maintenance Fees
Utility patent owners must pay maintenance fees at 3.5 years, 7.5 years, and 11.5 years after issue.11United States Patent and Trademark Office. Maintain Your Patent Miss any of the three and the patent expires, no matter how many years remain on the base term. Design and plant patents do not require maintenance fees.12United States Patent and Trademark Office. MPEP 2504 – Patents Subject to Maintenance Fees
Each fee has a six-month window before its due date and a six-month grace period after, with a surcharge for grace-period payments.13United States Patent and Trademark Office. USPTO Fee Schedule If the grace period passes unpaid, the patent expires. This is the most common reason utility patents die before their full term, and Patent Center’s maintenance fee record is the fastest place to catch it.
The Full Verification Checklist
- Confirm the patent type and identify the base term: 20 years from earliest non-provisional filing for utility and plant patents, 15 years from grant for design patents filed on or after May 13, 2015, and 14 years from grant for earlier design patents.
- If the application was filed before June 8, 1995, calculate both 17 years from grant and 20 years from filing and use the later date.
- Add the Patent Term Adjustment shown on the face of the patent.
- Check for a Patent Term Extension if the patent covers a drug, device, or food or color additive.
- Review the file history for a terminal disclaimer, and if one exists, use the reference patent’s expiration date.
- For utility patents, verify every due maintenance fee has been paid, including any within a grace period.
A Lapsed Patent Is Not Always a Dead Patent
A patent that expired for a missed maintenance fee can be brought back. The owner can petition the USPTO to accept late payment if the delay was unintentional, and if the petition is granted the patent is treated as though it never expired.14Office of the Law Revision Counsel. 35 US Code 41 – Patent Fees; Patent and Trademark Search Systems
That matters if you plan to act on an apparent expiration. Someone who began making, using, or selling the patented invention during the lapse has the right to continue that specific activity after revival, and a court can also permit continued manufacturing where substantial preparation was made during the lapse.14Office of the Law Revision Counsel. 35 US Code 41 – Patent Fees; Patent and Trademark Search Systems These intervening rights protect what you were already doing, not new activities added after revival. Before relying on a patent that shows as expired for nonpayment, weigh the revival window against how much of your activity would qualify as an intervening right, and consider talking to a patent attorney.