Filing Date vs Priority Date: Key Patent Deadlines Explained
Filing Date is the day you submit your complete patent application. Priority Date is the earliest date you can claim from a prior filing—often a provisional—that establishes when your invention was first disclosed.
Founders sprint to the USPTO, thinking “submitted = safe,” then panic when a rival files earlier. They confuse the protective shield (Priority Date) with the paperwork timestamp (Filing Date) and risk losing first-to-file rights.
Key Differences
Filing Date starts examination and the 20-year term. Priority Date secures novelty against later disclosures. One sets the clock; the other locks the gate.
Which One Should You Choose?
You don’t choose—you claim. File a provisional to lock the Priority Date, then a non-provisional within 12 months to preserve it. Miss the window and only the Filing Date remains.
Examples and Daily Life
You email your prototype to investors on March 1, file a provisional March 15, then a PCT March 15 next year. March 15 is your Filing Date, but March 1 is your Priority Date, beating any April disclosure.
Can I change the Priority Date later?
No. Once set, it’s fixed; only new applications can earn new priority.
Does the Filing Date affect patent term?
Yes. The 20-year term runs from the non-provisional Filing Date, not the Priority Date.