Patent Novelty · Filing Deadlines
The Patent Grace Period
US law gives inventors one year after their own public disclosure to file a patent application. But the grace period is narrower and more dangerous than most inventors realize.
The rule in plain English
If you publicly disclose your invention, you have exactly 12 months to file a US patent application before your own disclosure becomes prior art against you. But if a third party independently discloses or files a patent on the same invention, the grace period does not protect you — that is prior art regardless of timing.
The statute
35 U.S.C. § 102(b)(1) — what it actually says
“A disclosure made 1 year or less before the effective filing date of a claimed invention shall not be prior art to the claimed invention under subsection (a)(1) if — (A) the disclosure was made by the inventor or joint inventor or by others who obtained the subject matter disclosed directly or indirectly from the inventor or a joint inventor; or (B) the subject matter disclosed had, before such disclosure, been publicly disclosed by the inventor or a joint inventor or another who obtained the subject matter disclosed directly or indirectly from the inventor or a joint inventor.”
35 U.S.C. § 102(b)(1) (AIA, effective March 16, 2013)
In plain English: a disclosure is not prior art if (A) it came from you or your joint inventors, or (B) whoever disclosed it got the information from you. This covers leaks — if a journalist published your invention because they got it from you, that publication is within the grace period.
What it does not cover: an independent third party who arrives at the same invention through their own work and publishes or files before you. That is prior art, full stop, even if they did it yesterday and you filed today.
What changed in 2013
Pre-AIA vs. AIA grace period
The America Invents Act (AIA), effective March 16, 2013, changed US patent law from first-to-invent to first-inventor-to-file. The grace period changed with it.
Pre-AIA (before March 16, 2013)
First-to-invent. You could 'swear behind' a competitor's filing by proving you invented first. A one-year grace period existed for public use and sales.
Mostly relevant for old patents only. If the application was filed before March 16, 2013, pre-AIA rules apply.
AIA (March 16, 2013 onward)
First-inventor-to-file. You cannot swear behind a competitor's filing. The grace period protects only your own prior disclosures — not independent third-party disclosures.
The key trap: a competitor who independently publishes the same invention within your grace period still creates prior art you cannot overcome.
Scenarios
When the grace period saves you — and when it does not
The international trap
The grace period ends at the US border
The US one-year grace period does not apply outside the United States. Most countries — including all major economies — require absolute novelty before the patent filing date. Your public disclosure is immediately fatal to patent rights in these jurisdictions:
European Union
No grace period (EPC Art. 54)
United Kingdom
No grace period
China
No grace period
Japan
6-month grace period — very limited scope
South Korea
12-month grace period — inventor's own disclosure only
Canada
12-month grace period (inventor's own only)
Australia
12-month grace period (inventor's own only)
India
No grace period for most disclosures
The bottom line: If you want patent protection in Europe, China, or Japan, file a patent application (or provisional) before any public disclosure. The US grace period cannot save your international rights. File a PCT application within 12 months of your US priority date to lock in international rights.
Best practice
File before you disclose — always
Experienced patent practitioners universally advise: never rely on the grace period as a strategy. It exists as a safety net for accidental disclosures, not as planned timing. The correct approach:
File a provisional before any disclosure
A provisional application costs $2,000–$4,000 with counsel and establishes your priority date. File it before the paper submission, conference presentation, demo, or product launch. Then you can disclose freely — your filing date is protected.
Convert to non-provisional within 12 months
The provisional lapses if you do not convert. File the full non-provisional application within 12 months of the provisional filing date. The non-provisional claims priority to the provisional's filing date for all subject matter the provisional adequately described.
File PCT within 12 months of the provisional
To preserve international rights, file a PCT application within 12 months of the provisional filing date. This gives you up to 30 months total before you must elect national phases in specific countries — time to evaluate whether international filing is worth the cost.
FAQ
Grace period questions
How long is the US patent grace period?
Under 35 U.S.C. § 102(b)(1), the US patent grace period is exactly one year. If you publicly disclose your invention, you have 12 months from the date of that disclosure to file a patent application. If you file on day 366 or later, your own disclosure becomes prior art against your application and you lose the ability to patent the invention in the US. The one-year period runs from the earliest qualifying public disclosure.
Does the grace period protect against a competitor who publishes the same invention independently?
No — this is the most dangerous misunderstanding of the grace period. Under the AIA (effective March 16, 2013), if a third party independently discloses or patents the same invention before your filing date, that disclosure is prior art against you, even if it occurred within your one-year grace period. The grace period only protects your own prior disclosures, not identical third-party disclosures. This is a critical difference from the pre-AIA first-to-invent system, where you could swear behind a competitor's filing by showing you invented first.
Does the US grace period apply to patent applications filed in Europe or other countries?
No. Most countries have no grace period at all — the European Patent Convention (EPC) requires absolute novelty before the filing date. A public disclosure anywhere in the world before your patent filing date is fatal to European, Japanese, Chinese, and most international patent applications. The narrow exceptions (Germany has a 6-month grace period for exhibition disclosures; Japan has a 12-month grace period for specific types of disclosures) are limited and unreliable. If you want international patent protection, file before any public disclosure or use a provisional application as a placeholder.
Does an academic paper or conference presentation count as a public disclosure that starts the grace period?
Yes. Any publication that makes the invention publicly available starts the one-year grace period in the US. This includes: journal articles (even preprints on arXiv, SSRN, or bioRxiv), conference presentations and posters, thesis submissions, trade show demonstrations, product launches, blog posts, YouTube videos, and any other public disclosure. The date of public availability — not the date you delivered the talk or published the final version — controls. A paper posted on arXiv on January 1 starts the grace period on January 1, even if the journal publishes it in March.
Can I use a provisional patent application to protect the grace period?
Yes — a provisional patent application filed before your public disclosure is the best practice. A provisional application establishes your filing date (priority date) while giving you 12 months to file a non-provisional. Any disclosures you make after the provisional filing date are not prior art against your own application, and you have a filing date that predates any later third-party filings. The provisional buys you 12 months of development and fundraising time with patent-pending status, while protecting both the US grace period and, critically, your ability to seek international patents. The provisional must adequately describe the invention you later claim in the non-provisional.