Inventor grace period: When is it too late to file a US patent after disclosing invention?

Can prior public disclosures of my invention kill my chances of getting a patent?

Revealing your invention to the public before filing a patent application can disqualify you from patenting in certain countries. The rules depend upon each specific country, so keep these timelines in mind before you plan on disclosing your invention to the public. The US offers an inventor grace period as discussed below.

Is it too late for you to file a patent? Contact Vic at or call (949) 223-9623 to explore your options.

Is there an inventor grace period for filing US patent applications?

Yes, a 1-year grace period applies for US patent filings for the inventor’s own prior public disclosures. This means that inventors have up to one year from their earliest date of public disclosure of their invention to file a US patent application. The previous disclosure must have been made by the inventor, a joint inventor, or another who obtained the subject matter directly or indirectly from the inventor.

For example, if you publicly disclosed your product or concept for the first time at a trade show, you can still file a US patent application within 12 months of that earliest public disclosure.

This 1-year grace period may also be available to foreign inventors, but foreign applicants should check their own country’s laws requiring foreign filing licenses for inventions made in their origin country.

This inventor grace period also applies to any patent publications by the same inventor. For example, if a foreign patent application by the same inventor were to publish prior to the US filing date and a priority claim was not possible, then a US patent application may still be filed within one year of the foreign publication date.

What if more than one year has passed since your earliest public disclosure?

If the unique features of your product are primarily ornamental (how they look vs. how they work), you might have the option to file a copyright application if those features meet the separability test.

Another option is to consider any improvements or modifications that have not been publicly disclosed or sold more than one year ago. You might be able to file a US patent application on the improved or modified concept. Keep in mind, however, that your current and older product versions may serve as prior art against your patent application for the new version.

Inventor grace period for foreign patent protection?

What is the Absolute Novelty Bar?

If you have publicly disclosed your invention prior to filing a patent application, then you will be barred from patenting that invention in most foreign countries. This rule,  known as the absolute novelty bar, requires that you avoid public disclosures of your invention prior to filing a patent application if you want to apply for foreign patents.

Is it necessary to apply in each foreign country prior to any public disclosures?

No. To keep your foreign filing options open, you simply need to file a patent application in a single country (e.g., US) prior to disclosing your invention to the public. This will secure patent pending status and a patent filing date, known as the priority date if the filing is your first patent application for this invention. You must then timely file your foreign applications within a certain time period and link those foreign applications to your priority application by including an appropriate priority claim.

Which foreign countries have grace periods for an inventor’s own prior public disclosure?

Certain countries provide a limited grace period for the inventors’ own disclosure of their inventions to the public:

  • Canada: 12 months
  • Japan: 12 months (effective June 9, 2018 for public disclosures made on or after Dec. 9, 2017)
  • S. Korea: 12 months
  • Russia: 6 months
  • Europe: The European Patent Convention (EPC) has a conditional 6-month grace period applicable in only certain circumstances
  • See this list of international patent grace periods

What if it’s too late to claim priority to a published foreign application?

Applicants who wish to file US patent applications related to their foreign applications may do so within certain time periods (i.e., 12 months for utility filings and 6 months for design filings). If there was an unintentional delay, an additional 2-month grace period may apply.

What if an applicant has already blown past the above deadlines as well as the 2-month grace period? Can the applicant still file a US application for the same invention covered in the previously filed foreign application(s)? The answer depends upon the publication date of the applicant’s prior foreign filings.

Keep in mind that inventors have a 1-year grace period to apply for US patents. Therefore, if the publication date of the applicant’s own foreign patent filing is less than a year old, the applicant may still file a US patent application. Without a priority claim to the foreign application, however, such an applicant may potentially face more prior art which can be cited against the US application.

Are you within 1-year inventor grace period for US patent protection?

If so, email US patent attorney Vic Lin or call (949) 223-9623 to see how we can quickly file your US patent application before it’s too late.

If you think you might be too late, let’s talk and explore any other options.

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