§102 · Novelty
Is your invention actually new?
A patent has to be novel— not already available to the public before you filed. Section 102 defines what counts as that “prior art,” sets the first-to-file rule, and gives you a one-year grace period that's easy to misunderstand. Here's how it works.
What counts as prior art
The five §102 bars
If any of these happened before your effective filing date, the invention may already be in the public domain — and unpatentable.
Patented
The invention was already patented anywhere in the world before your effective filing date.
e.g. An earlier granted patent — US or foreign — disclosing the same invention.
Described in a printed publication
It was described in any publication, in any language, anywhere — including journals, theses, websites, and conference papers.
e.g. A research paper or a product manual posted online before you filed.
In public use
The invention was used publicly in a way that made it available to the public before filing.
e.g. Demonstrating the working invention at a trade show without confidentiality.
On sale
The invention was sold or offered for sale before filing. Even a confidential commercial sale can trigger this bar.
e.g. Offering the product to a customer — the Supreme Court confirmed in Helsinn v. Teva (2019) that even a secret sale counts.
Otherwise available to the public
A catch-all: any other way the invention became publicly accessible before your effective filing date.
e.g. An oral presentation, a public demonstration, or a posting that doesn't fit the other categories.
The safety net
The one-year grace period
The US gives inventors a limited grace period for their own disclosures — but it is narrower than most people think, and it does not travel abroad.
One-year window
A disclosure made one year or less before your effective filing date is not prior art against you — if it qualifies under the exceptions below.
Your own disclosure is excused
A disclosure by the inventor (or someone who got the information from the inventor) within that year does not count against your application.
It does not save foreign rights
Most countries have absolute novelty — any public disclosure before filing bars a patent there. The US grace period is a domestic safety net, not a strategy.
A competitor can still beat you
Disclosing first starts the clock but doesn't reserve the invention. Under first-to-file, a third party who files before you can still take priority.
How it's judged
Three rules that decide novelty
- 01
Anticipation needs a single reference
To destroy novelty, one prior-art reference must disclose every element of the claim, arranged as claimed. If it takes combining two references, that's obviousness (§103), not anticipation.
- 02
First to file, not first to invent
Since the AIA took effect in 2013, priority goes to the first inventor to file an application — not the first to come up with the idea. File early.
- 03
The effective filing date is the line
Everything is measured against your effective filing date, which a provisional application can push earlier. Anything public before that date is potential prior art.
Check your idea
Novelty is one of four gates.
Your invention must also be eligible (§101), non-obvious (§103), and fully described (§112). The cheapest first move is a prior-art search to see what's already out there.
Plain-English education, not legal advice. The on-sale and public-use bars in particular are full of traps — if you have disclosed, sold, or demonstrated your invention, talk to a registered patent attorney before the clock runs out. PatentBrief is not a law firm.
The four requirements