Every patent has a limited life span and will eventually expire. The purpose of the patent system is to promote development in science. To encourage innovation, the United States Patent and Trademark Office (USPTO) rewards inventors with a patent for their invention.
This patent allows the inventor to make money from the invention without competition by preventing others from making or using it. This level of control can prevent others from using the invention for research purposes which may hinder the development of science.
Patents expire to balance the incentive a patent provides with the drawback that a patent may restrict research. When a patent expires, it is no longer valid and cannot be used to prevent people from copying the invention. This allows anyone to freely use the invention in their research.
If patents never expired, the patent owner could forever prevent others from conducting research using their invention. This would allow the patent owner to control any future technological developments based on their invention. Patents expire to prevent the control a patent provides from forever restricting progress in that technological area.
Patent Protection Periods
Each patent application is assigned an application date corresponding to the day the application was filed. This date is called the “effective filing date.” The expiration date of a patent is based on the effective filing date and the type of patent.
If a provisional patent application is used, the effective filing date is the date the provisional application was filed. The USPTO takes two years on average to approve an application, so inventors have even less time to make use of a patent than its maximum life. The USPTO does not publish patent expiration dates but provides a patent term calculator.
How Long Does a Utility Patent Last?
A utility patent has a maximum life of 20 years after the date the application was filed. Utility patents may also expire early if maintenance fees are not paid.
How Long Does a Design Patent Last?
A design patent has a maximum life of 15 years after the date the application was filed.
How Long Does a Plant Patent Last?
A plant patent has a maximum life of 20 years after the date the application was filed.
Maintenance fees don’t apply to design or plant patents.
Reasons a Patent Can be Terminated Early
A patent may be terminated early for several reasons including:
- Failing to pay maintenance fees
- A court finds the patent invalid
- The inventor gives up their rights
To keep a utility patent active, the patent holder must pay maintenance fees at 3.5 years, 5.5 years, and 11.5 years after the patent is granted. If the maintenance fees are not paid, the patent expires.
Patents may also expire if a court of law finds them invalid, such as in a patent infringement lawsuit. Additionally, the owner of a patent may give up their rights through a terminal disclaimer. If the owner of a patent files a terminal disclaimer, they grant their patent rights to the public. The owner of the patent can disclaim the entire patent or a particular part. Any part of a patent that is disclaimed can no longer be used to prevent someone from making and using that aspect of the invention. The patent does not expire, and any part of the patent not disclaimed is still enforceable.
A terminal disclaimer does not cause a patent to expire, but it has the same effect.
Timeline for a Patent
The patent application process and timeline vary based on the invention, technological field, and type of patent. The general timeline of the life of a patent may look like this.
What Happens after the Patent Protection Period Ends?When a patent expires all the rights granted to the patent holder expire with it. The holder can no longer prevent others from making, using, or selling the invention. License agreements to collect royalty payments from the patent are no longer enforceable. The invention then passes into the public domain so that anyone can use it.
Approximate Timeline for a Utility Patent
| Time | Total Time | |
|---|---|---|
| Initial idea | 0 | 0 |
| Research and development | 3 months | 3 months |
| Preliminary searching | 1 month | 4 months |
| Provisional patent application | 2 months | 6 months |
| Nonprovisional patent application | 1 year | 18 months |
| Patent granted | 2 years | 42 months |
| Maintenance fees 1 | 3.5 years (after grant) | 7 years |
| Maintenance fees 2 | 5.5 years (after grant) | 9 years |
| Maintenance fees 3 | 11.5 years (after grant) | 15 years |
| Expiration | 20 years (after application) | 20 years 6 months |
Sheldon Brown
Sheldon received his training of the patent system at the United States Patent & Trademark Office. He works with universities and consultants to provide analytics and guidance for technology commercialization from patents.
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