The priority date may be earlier than the actual filing date of an application. The priority date determines whether another patent filing or publicly available document qualifies as prior art against one's patent application.A valid priority claim provides an earlier cut-off date for when a piece of prior art needs to have been disclosed to the public. If this is a later date, you may also request priority within four months of the date on which you submitted your new application. A priority claim is made to an earlierfiled patent application. For example, an Applicant can claim priority in a later-filed patent application. A later patent application can claim priority from more than one priority patent applications filed within the preceding year. In a situation with only one patent application, the priority date is the same as the filing date for the single application. It is the priority date which is used when determining if the invention is new and inventive. It's counterintuitive, but waiting to file a patent application is almost always the best option instead of rushing to get an early filing date.