How to Do a Patent Search: What You Can Do Yourself and What You Can’t
How to do a patent search: brainstorm keywords for your invention, use them to find classification codes, then search US patents and published applications in those classes and read the closest results closely. Widen the search to foreign patents and technical literature last. A self-run search is a useful first filter, not a guarantee.
What does a patent search actually tell you?
It tells you whether earlier patents or publications describe something close to your invention. The most common type is a patentability search, which checks novelty and non-obviousness before you spend money filing.
A patentability search is different from a freedom-to-operate analysis. The first asks whether you can get a patent. The second asks whether your product could infringe someone else’s. Our post on patent search versus freedom to operate explains why one cannot stand in for the other.
How to do a patent search step by step
Follow the USPTO’s preliminary search outline: brainstorm terms, find classification codes, search those classes, review each result, and then look beyond US documents. The steps are simple to list and slow to do well.
Brainstorm keywords. Describe the invention’s purpose, makeup, and use in plain words.
Find classification codes. For utility inventions, run your keywords through the USPTO’s Classification Text Search Tool to find Cooperative Patent Classification (CPC) codes.
Confirm the codes fit. Read each code’s definition to make sure it matches what your invention does.
Search inside those classes. Use Patent Public Search to find published applications and issued US patents in the codes you chose.
Read each close result carefully. Compare its claims and description to your invention, feature by feature.
Widen the search. Check non-US patent databases and non-patent literature, such as WIPO’s Patentscope for patents and its Global Design Database for designs.
Keep a log as you go. Write down every search term, every code, and every document that came close, because you will need that record later.
Which free tools can you use?
Patent Public Search is the main one. It is a free USPTO tool for US patents and published applications, with a basic mode for keywords and fields and an advanced mode for complex queries and tagging results. The USPTO says users will need a USPTO account to sign in starting November 7, 2026.
Other USPTO resources include Global Dossier, which shows file information for applications in a patent family across participating IP5 offices. Patent and Trademark Resource Centers are libraries that offer search help. The Henry E. Baker Public Search Facility at USPTO headquarters gives public access to patent information. The USPTO also lists Patentscope and Espacenet as international databases.
What are the limits of a DIY patent search?
A preliminary search is less thorough than the examiner’s. The USPTO says examiners often reject claims based on information an applicant’s search didn't uncover. A clean search result does not mean the path is clear.
Our inventor FAQs explain two reasons. First, results are only as good as the search parameters, and a few keywords without synonyms, variations, or classifications give a poor picture. Second, examination turns on obviousness, so features found in several references can be combined in a rejection.
There is also a legal duty. You and your attorney must disclose to the Patent Office information known to be material to patentability. If you run your own search, note what you find and pass it on. Failure to do so may result in a granted patent being held unenforceable.
What mistakes make a patent search unreliable?
Most bad searches fail from narrow vocabulary, shallow reading, and early stopping.
Searching one phrase. The same device may be called a “fastener,” a “retainer,” or a “clip” in different patents.
Reading only titles and abstracts. The claims define what a patent covers, so read them.
Stopping at US documents. A foreign patent or a journal article can matter just as much.
Telling people about the invention first. Public disclosure can cost you rights, as our post on the one-year clock explains.
When should you hire someone to run the search?
Hire help when the invention is valuable, the field is crowded, or you plan to rely on the result. Our practice areas page describes patent searching as much an art as a science, because many people do not understand the limits of keyword searches.
Clients turn to us to evaluate the patentability of an invention, find prior art that can be used against competitors in a third-party submission, or understand the patent landscape in a field. We also monitor competitor portfolios. Details are on our practice areas page.
Frequently Asked Questions
Is a patent search free?
The tools are free. Patent Public Search is a free USPTO tool, and the Patent and Trademark Resource Centers offer search help. Your time is the real cost, and hiring a professional adds a fee.
Does a patent search tell me if I can sell my product?
Not by itself. A patentability search and a freedom-to-operate analysis answer different questions, and finding no identical invention doesn't mean a product is safe to sell.
Do I need a search before filing a patent application?
A search helps you decide whether filing is worth the cost, and the USPTO lists a preliminary search as the first step to apply for a utility patent.
Talk to a Patent Attorney
Sleman & Lund LLP provides patent searching, patent preparation and prosecution, and offers free consultations for patent matters. Review our practice areas, then book a free consultation online or contact us.
Phone: (732) 795-0505
Email: sleman@patentspace.net
Office: 4400 U.S. 9 South, Suite 1000, Freehold, NJ 07728
Comments