Filing Date and Priority Date: What Is the Difference?
Timing plays a crucial role in intellectual property protection. It is no coincidence that one of the cornerstones of the international IP system is the Paris Convention, which grants applicants priority rights in more than 170 countries.
To use this system effectively and safely, it is essential to understand two key concepts: the filing date and the priority date.
What Is a Filing Date?
The filing date is the date on which an intellectual property application (trademark, patent, or industrial design) is validly filed and accepted by the competent IP office.
This date is of particular importance because:
statutory deadlines are calculated from this point in time,
the order of applications is assessed based on this date,
it serves as the default reference date if no priority is claimed.
Simply put, the filing date is the moment when the legal procedure officially begins.
What Is a Priority Date?
The priority date is the date of an earlier application on which a later application is based. The essence of priority is that the later filing is examined as if it had been filed on the earlier date.
This is especially important if:
protection is sought in multiple countries,
an international or regional application (e.g. EU filing) is planned,
there is a risk that third parties may file similar applications in the meantime.
Internal Priority
Internal priority arises when multiple applications are filed within the same country or legal system, and a later application claims priority from an earlier one.
This commonly occurs, for example, in patent filings, where a later patent application is filed for the same invention based on an earlier national application.
The purpose of internal priority is to preserve the time advantage of the original filing while allowing a more flexible filing strategy.
The filing date and the priority date may be identical, but in international or more complex filing strategies, they often differ.
How Much Time Is Available to Claim Priority?
Under the Paris Convention, the following priority periods apply:
Trademarks: 6 months
Industrial designs: 6 months
Patents: 12 months
This means that after filing a national application, the applicant has a limited period to initiate foreign or international procedures while retaining the original filing date.
If these deadlines are missed, the priority right is lost, and later applications will only enjoy protection based on their own filing dates.
In practice, priority must usually be claimed within two months after filing, and supporting documents relating to the earlier application must also be submitted.
Why Is This Especially Important in Practice?
Without priority rights, competitors may easily gain an advantage. For example, in trademark matters, the earlier rights holder can effectively act against later trademark applications, including through opposition proceedings.
Priority rights also allow applicants to gain valuable time for strategic decision-making: by filing first at national level, the applicant can secure an early date while still having several months to decide in which additional countries or systems protection should be pursued.
In patent cases, priority is essential to avoid self-destroying novelty. A prior national patent application could otherwise become novelty-destroying prior art for a later foreign filing. By claiming priority, the foreign application is examined based on the original filing date.