An effective filing date of a patent application is sometimes different than the actual filing date of the patent application. The effective filing date may be earlier than the actual filing date if an application claims “priority” to a previously filed and co-pending patent application. For example, a continuation application that claims priority to a parent application can have an effective filing date that is the actual filing date of the parent application.

For example, if Application One was filed on 1/1/2000 it would have a filing date of 1/1/2000. If during the pendency of Application One, the applicant files Application Two on 5/2/2021 and Application Two claims priority to Application One, Application Two would have an actual filing date of 5/2/2021 and an effective filing date of 1/1/2000.