Absolute novelty in patent law is the rule that an invention must be entirely new on the day you file, meaning any public disclosure anywhere in the world before your filing date destroys your right to a patent. The European Patent Office, China’s National Intellectual Property Administration, and most other major patent offices apply this standard with almost no exceptions. The United States, Japan, and South Korea soften it with a 12-month grace period, but that grace period does not travel: a disclosure that is forgivable at home can permanently bar protection in Europe, China, and dozens of other markets. The safest rule of thumb is simple. File before you disclose.
What a Disclosure Actually Is
The “state of the art” against which your invention is judged includes everything made available to the public anywhere in the world, by any means, before your filing date.1European Patent Office. European Patent Convention – Article 54 – Novelty Journal articles, conference papers, websites, patent publications, product catalogs, advertisements, investor pitches, trade fair demonstrations, media interviews, product sales, a video posted online — if the information reached the public, it counts.
There is one meaningful limit. A disclosure only qualifies as prior art if it gives enough technical detail that a skilled person in the field could actually reproduce the invention.2European Patent Office. PCT International Search and Preliminary Examination Guidelines – Enabling Disclosure of a Prior Document A vague reference to a concept, without enough substance to let someone build the thing, does not qualify. This is a thinner shield than most inventors assume. Describing how a device works to a crowd at a technology expo, publishing specifications in a sales brochure, or presenting data at an academic conference will usually cross the enablement threshold. Audience size does not matter either. Telling a single person who is not bound to confidentiality can be enough to place the invention in the state of the art.
Selling the Invention Counts, Even Under an NDA
Commercial activity is its own trap. Under 35 U.S.C. § 102(a)(1), an invention is barred from U.S. patent protection if it was “on sale” before the effective filing date.3Office of the Law Revision Counsel. 35 USC 102 – Conditions for Patentability; Novelty The test has two parts: the invention was the subject of a commercial offer for sale (not experimental use), and it was ready for patenting when the offer was made.4United States Patent and Trademark Office. MPEP 2152 – Detailed Discussion of AIA 35 USC 102(a) and (b)
The wrinkle catches many inventors off guard. A sale made under a confidentiality agreement still triggers the on-sale bar. The Supreme Court confirmed in 2019 that Congress did not change the meaning of “on sale” when it enacted the America Invents Act, and that a sale to a third party contractually bound to secrecy still qualifies as prior art.4United States Patent and Trademark Office. MPEP 2152 – Detailed Discussion of AIA 35 USC 102(a) and (b) An NDA can shield you from a public-disclosure argument. It does not shield you from the on-sale bar. The U.S. one-year grace period can rescue a domestic filing after an on-sale event, but absolute novelty jurisdictions offer no equivalent safety net for commercial activity.
Grace Periods: Broad, Narrow, and Absent
Not every country enforces absolute novelty the same way. The gap between the generous and the strict regimes is where global patent strategies go wrong.
The 12-Month Grace Countries
The United States provides a 12-month grace period. A disclosure made up to one year before the effective filing date is not prior art if it came from the inventor, a joint inventor, or someone who obtained the information from them.3Office of the Law Revision Counsel. 35 USC 102 – Conditions for Patentability; Novelty The grace period also covers a third party who independently publishes the same subject matter, provided the inventor publicly disclosed it first. Japan and South Korea each provide a similar 12-month window covering inventor-originated disclosures, though both require the applicant to affirmatively claim the grace period at or shortly after filing.
These broad grace periods can create a false sense of security. An inventor who presents research at a U.S. conference and files a U.S. application nine months later will probably be fine at home, in Japan, and in South Korea. That same presentation may have already destroyed novelty in Europe and China.
Europe and China: Narrow Exceptions Only
The European Patent Convention allows only a six-month window, and only in two situations: disclosures resulting from an evident abuse of the applicant’s rights, and displays at officially recognized international exhibitions.5European Patent Office. European Patent Convention – Article 55 – Non-prejudicial Disclosures An inventor who voluntarily publishes a paper or gives a talk gets no protection at all.
Article 55’s exceptions are also narrower than they sound. Evident abuse covers situations like a stolen blueprint, a hacked database, or a breached NDA leading to unauthorized publication. The applicant must show the disclosure resulted directly from clearly abusive conduct, not from an ordinary business dispute. The exhibition exception is limited to displays at official or officially recognized international exhibitions falling under the 1928 Paris Convention on international exhibitions (as revised in 1972). Ordinary trade shows, commercial expos, and industry conferences are not covered. The applicant must declare the exhibition at filing and submit a supporting certificate within the deadlines set by the implementing regulations.6European Patent Office. European Patent Guide – Novelty – Section 3.3.1 Basic Principles Both exceptions carry a hard six-month deadline running back from the European filing date. Miss the window or the paperwork, and there is no remedy.
China’s Patent Law contains a similar six-month grace period under Article 24, restricted to disclosures made during a national emergency in the public interest, displays at government-sponsored international exhibitions, publications at prescribed national-level academic or technical conferences, and unauthorized disclosures by third parties. Posting details on a website, talking to the press, or presenting at a non-qualifying conference receives no protection. Many other Patent Cooperation Treaty countries have no grace period at all, or follow an equally restrictive model.7World Intellectual Property Organization. Certain Aspects of National/Regional Patent Laws – Grace Period
Someone Else’s Unpublished Application Can Still Sink Yours
Absolute novelty regimes include a form of prior art that is invisible when you file. Under Article 54(3) of the European Patent Convention, the state of the art includes the contents of other European patent applications with an earlier filing date that publish on or after your own filing date.8European Patent Office. EPO Guidelines for Examination – State of the Art Pursuant to Art. 54(3) Applications typically publish 18 months after filing, so a competitor may have filed something nearly identical months before you without either of you knowing.
This “whole contents” prior art applies only to the novelty analysis, not to inventive step. The only practical defense is to file as early as possible. The earlier your priority date, the smaller the window in which someone else’s unpublished application can undercut you.
File First: Provisionals, Paris Priority, and the PCT
Because the entire novelty analysis turns on your filing date, the practical response to absolute novelty is to establish that date before any disclosure, sale offer, or unguarded conversation.
A Provisional Application as the Anchor
A U.S. provisional application is one of the cheapest ways to lock in a priority date. Filing fees start at $65 for micro entities and reach $325 at the standard rate.9United States Patent and Trademark Office. USPTO Fee Schedule The provisional establishes a filing date, gives you 12 months to file a non-provisional, and can serve as the basis for Paris Convention priority claims abroad.
A provisional only works, though, if it adequately describes and enables the invention. If the non-provisional later adds subject matter that was not supported in the provisional, only the properly described material gets the earlier priority date. The new material receives the non-provisional’s filing date. Any public disclosure of that new material between the two filings becomes prior art against those specific claims. Treating a provisional as a rough placeholder and expanding the invention later defeats the point of filing early.
Paris Convention Priority
The Paris Convention gives applicants a 12-month priority period for patents. Once you file in any member country, you can file in other member countries within 12 months and claim the original filing date as your priority date.10United States Patent and Trademark Office. Appendix P – Paris Convention Disclosures or competing filings that occur between your first filing and your later foreign filings are judged against the original priority date, not the later ones. This is the single most important mechanism for preserving novelty across borders. File somewhere before you disclose anything, then use that 12-month window to reach the foreign offices that matter.
The PCT Route
The Patent Cooperation Treaty does not grant patents, but a single international application preserves your right to enter the national phase in more than 150 countries. The international search report typically issues within nine months of the priority date, giving you an early look at the prior art before you commit to individual national filings.11United States Patent and Trademark Office. MPEP 1842 – Basic Flow Under the PCT The standard deadline for entering the national phase is 30 or 31 months from the priority date, depending on the country.12World Intellectual Property Organization. Time Limits for Entering National/Regional Phase Under PCT That buys roughly two and a half years after the first filing to decide which markets justify full national prosecution.
When You Have to Share Before Filing
Sometimes disclosure is unavoidable — you need a manufacturer to quote a build, an investor to evaluate the concept, or a lab partner to run tests. A disclosure made under a binding confidentiality obligation generally does not count as making the invention public. A signed non-disclosure agreement, executed before any technical details are shared, is the standard tool. Without one, a casual conversation with a business contact can be treated as a public disclosure.
Courts have recognized implied duties of confidentiality in some professional contexts: a dentist fitting a patient with a prototype device, a researcher sharing unpublished work with close university colleagues, a designer showing samples at a controlled-access event. The common thread is that the inventor kept meaningful control over who saw the invention and under what conditions. Relying on implied confidentiality is risky, though. The burden of proving the relationship carried an expectation of secrecy falls on the inventor, and outcomes turn on the specific facts. A written NDA removes the ambiguity.
Keep in mind the on-sale bar. An NDA can preserve novelty against a public disclosure argument, but if the conversation includes a commercial offer to sell the invention and the invention is ready for patenting, the U.S. on-sale bar attaches regardless of the confidentiality clause. Confidential negotiations that involve pricing, delivery, or purchase terms deserve the same urgency around filing as a public launch would.
If a Third Party Discloses Without Authorization
When someone else discloses the invention without permission, the U.S. system offers a route to neutralize the disclosure. Under 35 U.S.C. § 102(b)(1), a disclosure made within the one-year grace period is not prior art if it was made by someone who obtained the subject matter from the inventor, or if the inventor had already publicly disclosed the subject matter before the third party did.3Office of the Law Revision Counsel. 35 USC 102 – Conditions for Patentability; Novelty If an examiner cites the disclosure, the applicant can respond with an affidavit or declaration under 37 C.F.R. § 1.130 showing that the disclosure falls within an exception.4United States Patent and Trademark Office. MPEP 2152 – Detailed Discussion of AIA 35 USC 102(a) and (b)
These remedies work in the United States. They do not help in absolute novelty jurisdictions. In Europe, only the narrow “evident abuse” exception under Article 55 EPC offers any relief, and it demands stricter proof and a tighter timeline. The practical takeaway is the same as everywhere else in the novelty analysis: the earlier you file, the less exposure you carry.