In general, the rule is that a utility patent application lasts 20 years from its filing date. However, this simple rule is modified by a number of adjustments, and in my experience as a patent attorney, an exact determination of the life of a non-provisional utility patent application can be complicated and depends on the original priority date for continuing applications.  To illustrate, the patent life may be affected by several factors including:

  • Maintenance Fees: In some cases, patents require maintenance fees to be paid at certain intervals to keep the patent in force. If the fees have not been paid, the patent will be considered expired.
  • Patent Term Adjustment: In some cases, the patent term may be adjusted based on various factors such as delays in the examination process or regulatory approvals.
  • Patent Term Extension: In some cases, the patent term may be extended for certain types of patents, such as for pharmaceuticals, to compensate for regulatory delays such as FDA related delays.
  • Supplementary protection certificate: In the European Union, supplementary protection certificates (SPCs) can be obtained for certain medicines to extend the life of a patent for up to five years. As noted above, the USPTO has a similar patent life extension process to compensate for FDA related delays.

How To Check if a Patent is still Alive

The length of time a patent lasts depends on the type of patent and when it was filed. Utility patents, which cover new and useful processes, machines, manufactures, or compositions of matter, or new and useful improvements thereof, generally last for 20 years from the date of filing. Design patents, which cover new, original, and ornamental designs for an article of manufacture, generally last for 15 years from the date of grant. Plant patents, which cover asexually reproducible plants that have been asexually reproduced, generally last for 20 years from the date of grant. However, as noted above, the general rule will be adjusted on a case-by-case basis taking into consideration the factors mentioned therein.

For most purposes, you only need to find out if the patent is still in effect and not the exact date of patent expiration. A patent is considered “alive” if it has not expired or been declared invalid by a court or the patent office. There are several ways to determine if a patent is alive:

  1. Checking the patent status: The status of a patent can be checked through the United States Patent and Trademark Office (USPTO) website or by searching for the patent number on the website of the relevant national patent office. The status will indicate whether the patent is active or expired.
  2. Reviewing the expiration date: Patents have a set term of protection, typically 20 years from the date of filing, after which the patent expires and the invention becomes part of the public domain. The expiration date of a patent can be found in the patent document or through a search of the patent database.
  3. Conducting a validity search: A validity search can be done to determine if any court or administrative proceedings have been taken against the patent, which could result in the patent being declared invalid. This search can be conducted through the USPTO database or by hiring a patent attorney.
  4. Monitoring for infringements: Monitoring for infringement can help to determine if a patent is being enforced, which is a sign that the patent is alive. If a patent owner is not enforcing their patent, it may be because the patent is invalid or has expired.
  5. Checking the maintenance fee: Patents require maintenance fees to be paid at certain intervals to keep the patent in force. If the fees have not been paid, the patent will be considered expired.

The determination of the life of a patent depends on the type of patent and the laws of the country in which it was granted. In general, the life of a utility patent (a patent for a new and useful process, machine, manufacture, or composition of matter, or a new and useful improvement thereof) in the United States is 20 years from the date of filing, while the life of a design patent (a patent for a new, original, and ornamental design for an article of manufacture) is 15 years from the date of grant. In some countries, the life of a patent may be different, and in some cases, it may be subject to extension under certain circumstances.

How Priority Claims can Affect Patent Life

I. Continuing Applications

A patent granted for a continuation, divisional or continuation-in part application filed after June 8, 1995 will have a term of twenty years starting from the date of the earliest application under 35 U.S.C. 120, 121 and 365(c) or 386(c), regardless of whether a claim for a benefit under 35 U.S.C. 120, 121 or 365 (c) were filed before June 8, 1995.

II. International Applications

Patent granted upon an international application that was filed after June 8, 1995 is eligible for national recognition under 35 U.S.C. Sectiono 371. The term of a 371 application will end twenty years after the date of the international filing. A continuation, or continuation-in-part, claiming benefits under 35 U.S.C. 365(c) to an international application designating the United States will end twenty years after the parent international filing date.

III. Foreign Priority

35 U.S.C. Foreign priority is therefore not considered. The term of an application claiming priority under 35 U.S.C. 119, 365(a), (365(b), 386(1)a, or 386(a) ends 20 years after the filing date of the United States application and the foreign priority claim is not counted in the lifetime determinaton.

IV. Domestic Benefit Under 35 U.S.C. 119(e)

Domestic benefit under 35 U.S.C. 119(e) for a U.S. provisional application does not count for the life determination under 35 U.S.C. 154(a)(3).  This is how you can extend the non-provisional patent life using provisional applications and converting to a non-provisional within one year.

V. Expiration Date for Patents With Terminal Disclaimers

It is usually necessary to review the text of the terminal disclaimer within the patent file history to determine the “original expiration day” of a patent subjected to a terminal disclaimer. If the disclaimer excludes the terminal portion, or any part of the term of the patent that would exceed the expiration dates of an earlier issued patent then the expiration of the earlier issued.

VI. Patent Term Extensions / Adjustments

MPEP Section 2710 provides information on patent term extensions and adjustments to delays caused by the USPTO for utility and plant patents that are issued on applications received after June 8, 1995.

For medical/pharmaceutical/biotech applications, patent term extensions may be available under MPEP Section 2750 for FDA premarket regulatory review delays. The premarket regulatory review of 156 is distinct from any extension available under the current and former 35 U.S.C. 154.

VII. How This Information Appears On The Face Of The Patent

On the first page of the patent, there is a Notice section on the top left which indicates the presence of PTA, PTE and terminal disclaimers (TD).  Because PTA can be modified by petitions following issuance, please refer to Patent Center for accurate PTA and PTA values.   The presence of a terminal disclaimer alerts you to inspect the Image File Wrapper in PAIR for terminal disclaimer documents for detailed information.  If a TD exists, you will have to perform expiration calculations for the referenced patent before you can finish the current patent’s calculation.

VIII. Patent Center Shows Extension Determination Details

While knowing the rules can help in case the PTO makes life adjustment mistakes, in general the PTO is right.  For informally determining life time extensions, you can rely  on the PTO to do the calculation for you.  Just head over the USPTO Patent Center at .  

Patent Center replaces the old Public PAIR portal and does not require a password to use.

To look up a granted patent, you will select “Patent Number” and enter a valid U.S. Patent number and click on the search icon to start your search.  Of course you can look up pending applications with the right selection as well.

The initial PAIR screen (Application Data) contains several required pieces of information to determine your patent term.   It also has tabs to other data that is required. On this screen you can obtain the Application Number (used for Fee search), Filing Date, Application Type and Issue Date (Grant Date).

You can see all documents in the file wrapper if you click on the Documents and Transactions tab:

Continuity Data is used to determine domestic filing date benefits derived from being a continuation, continuation-in-part or divisional application.

If any Patent Term Adjustments or Patent Term Extensions under 35 U.S.C. § 154 exist, the amounts will be listed under their own tabs on the left side

You can check if payments on maintenance fees are up to date by selecting the Fee Payment History, but in this case there are none.

You can also see the authorized attorneys listed in the Address and Attorney tab

Any assignments are shown in the Assignment tab

Any prior art cited by the inventor is shown in the Display References tab. You can order copies in the Order tab.

There is a special page for Patent Term Extensions under 35 U.S.C. § 156:

In sum, the determination of the exact patent expiration date can be complicated. However, in certain industries such as the pharmaceutical industry, every day of patent protection can mean millions in revenue that could have gone to generic drugs. If you are in such a sensitive space, you should consult with a patent attorney or the relevant national patent office to understand the specific laws and regulations regarding patent life and any potential extensions or adjustments that may apply.