Before you invest in a patent application, you want to know one thing: has someone already done this? A patent search is how you find out. It will not give you a definite answer, but a careful search can save you from filing on something that already exists, and it gives you and your attorney a clearer picture of how to describe what is truly new about your invention.
The short version: describe your invention in plain words, turn that into keywords and classifications, search the U.S. Patent and Trademark Office (USPTO) database and other free tools, then read the claims and drawings of the closest results. Our patent attorneys at Jafari Law Group run and review these searches for inventors from our office in Irvine, California. Here is how to do a first search yourself, and where its limits are.
Why Search Before You File
Under federal law, “prior art” is broad. It includes anything patented, described in a printed publication, in public use, on sale, or otherwise available to the public before your filing date (35 U.S.C. § 102(a)(1)). It does not matter which country it appeared in or whether it was ever sold in the United States.
The USPTO examiner will search the prior art anyway when reviewing your application. Searching first puts you ahead of that, and it helps you:
- Avoid spending time and resources on an invention that is already known.
- Spot what makes your invention different, so the application can focus on it.
- Draft claims that stand apart from existing patents from day one.
- See which companies are active in your field.
There is no legal requirement to search before filing. But if you know about prior art that is material to patentability, you have a duty to disclose it to the USPTO (37 C.F.R. § 1.56). Inventors and their attorneys usually do that by filing an Information Disclosure Statement.
Four Kinds of Patent Searches
People use the phrase “patent search” for several different jobs:
- Patentability (novelty) search: Is your invention new and not obvious? This is the search to run before filing.
- Freedom-to-operate search: Would making or selling your product infringe someone else’s active patent? This is a different question, and it matters before launch.
- Validity search: Is an existing patent vulnerable because of earlier prior art? This usually comes up in a dispute.
- State-of-the-art search: What has been done in a field generally? Useful for research and product planning.
A product can be patentable and still infringe someone else’s patent. That surprises many inventors. If you are about to manufacture or sell, a patentability search alone does not tell you whether you are clear to do so. That is the job of a freedom-to-operate review, and the stakes include patent infringement claims.
Step by Step: A Preliminary Search You Can Do Yourself
The USPTO publishes its own strategy for preliminary searches. Our version, based on that guidance, looks like this:
- Describe the invention in a few sentences. What does it do, what is it made of, and how does it work?
- Brainstorm search terms. List keywords, synonyms and technical terms. A “bottle” may also be a “container,” “vessel” or “flask.”
- Run keyword searches in the USPTO’s Patent Public Search tool and in other free databases.
- Review the closest results in depth. Read the abstract, look at the drawings, and read the claims, because the claims define what the patent actually covers.
- Find the classification. Note the Cooperative Patent Classification (CPC) codes on the most relevant results, then search those classes to find patents that use different words for the same idea.
- Follow the citations. Each patent lists earlier references it cited, and later patents may cite it. Both lead you to related art.
- Widen the search. Check foreign patents and non-patent literature: journal articles, product listings, user manuals, videos and crowdfunding pages.
- Keep a record. Note the databases, search terms and results you reviewed, and save copies of the closest references.
Free Tools to Use
- USPTO Patent Public Search: The USPTO’s main search tool for U.S. patents and published applications. It replaced the older PatFT and AppFT databases. As of November 7, 2026, the USPTO requires users to sign in with a USPTO account to use it, so set one up before you start.
- Espacenet: The European Patent Office’s free database, with patents from many countries.
- WIPO PATENTSCOPE: The World Intellectual Property Organization’s database, which includes international (PCT) applications.
- Google Patents: A widely used free search engine for patents and some non-patent literature.
- Patent and Trademark Resource Centers: Libraries around the country designated by the USPTO, where staff can train you to search.
What a Search Cannot Tell You
Even a careful search has blind spots:
- Unpublished applications. Most U.S. patent applications are published about 18 months after their earliest filing date (35 U.S.C. § 122(b)). Anything filed within that window, and some applications that are never published, will not show up.
- Obviousness. An invention can be new and still be unpatentable if it would have been obvious by combining earlier references. Judging that takes experience with how examiners and courts apply the law.
- Products and disclosures that are hard to find. A product sold years ago, or a talk given at a conference, can be prior art even if it is not in any database.
- Legal meaning. Whether a reference actually anticipates your claims, or whether your product falls within someone else’s claims, is a legal question.
What to Do if You Find Something Similar
Finding a similar patent is not necessarily the end of the road. Many patents cover improvements on earlier inventions. Look closely at what the earlier patent claims and what it leaves out. Your invention may differ in a way that supports narrower but still valuable claims, or its appearance may support a design patent.
If the similar patent is still in force and your product would fall within its claims, that is a freedom-to-operate concern rather than a patentability one. Talk with a patent attorney before launching, and do not copy the patented design.
Searching for Design Patents
Design patents protect how a product looks, so keyword searches often miss them. Use the design classifications, browse the drawings, and search by the type of product. Image-based search features in some databases can help. Because appearance is judged visually, compare drawings side by side rather than relying on titles.
When to Bring in a Patent Attorney
A do-it-yourself search is a good first step, and we encourage it. It usually makes the first conversation with your attorney more productive. A patent attorney adds a professional search, a review of the results against the legal tests, and a patentability opinion that shapes how the application is drafted. Before you manufacture or launch a product in a crowded field, a freedom-to-operate review is worth considering as well. When you are ready to file, our guide explains the steps to patent an idea, including whether a provisional application makes sense for you.
Frequently Asked Questions
Can I do a patent search myself?
Yes. The USPTO’s Patent Public Search, Espacenet, WIPO PATENTSCOPE and Google Patents are free. A self-search is a useful start, but it cannot judge obviousness or find unpublished applications.
Is a patent search required before filing?
No. But you must disclose material prior art you know about to the USPTO, and a search helps you draft stronger claims.
What is the difference between a patentability search and a freedom-to-operate search?
A patentability search asks whether your invention is new. A freedom-to-operate search asks whether making or selling your product would infringe someone else’s active patent.
Why does a search miss some applications?
Most applications are published about 18 months after filing, so recent filings are hidden from any search.
What if my search finds a patent just like my idea?
Read its claims closely. You may still have patentable differences, or you may need to change your design. A patent attorney can help you weigh the options.
Talk With a Patent Attorney About Your Search
A good search makes for a better application and fewer surprises later. Jafari Law Group is based in Irvine and serves inventors and businesses throughout Orange County. Our attorneys are registered to practice before the USPTO, our founder has a background in electrical engineering, and our team has drafted and filed more than 400 patent and trademark applications.
To review your search results or plan a filing, talk with a patent attorney at our Irvine office. If you already ran a search, bring what you found. Request a free evaluation online or call 949-362-0100.