Legal Definitions - effective filing date

Definition: The date that a patent application is considered to have been filed. This date is important because it determines the priority of the invention and the eligibility to file in other countries. It is also the date that closes the door on prior art and establishes the date of constructivereduction to practice.

• If an inventor files a patent application on January 1, 2021, that is the effective filing date. Even if the application is not approved until later, the inventor can claim priority over any similar inventions filed after that date.
• If a patent application is a continuing application, the effective filing date may be the same as the parent filing date. This means that the priority of the invention is based on the original application.

These examples illustrate how the effective filing date is important in determining the priority of an invention and the eligibility to file in other countries. It also shows how the effective filing date can be the same as the parent filing date for continuing applications.