Patent search guide
Types of patent searches, and which one you need
By Mahish Guru, Co-founder and CEO, PatentAssist.ai
Updated
"Do a patent search" can mean four different jobs with four different questions, scopes and deliverables. Picking the wrong one is expensive: a patentability search will not tell you whether you can sell a product, and a freedom-to-operate search will not tell you whether you can patent it. This page compares the main types for the US and Europe and links to a detailed guide for each.
Quick answer
- Filing a patent? Patentability search.
- Launching a product? Freedom-to-operate search.
- Facing or holding a patent in a dispute? Invalidity or validity search.
- Planning R&D or a deal? Landscape or state-of-the-art search.
The search types compared
| Search | Purpose | When | What is searched | In force or all | Typical deliverable |
|---|---|---|---|---|---|
| Patentability (novelty) | Can I get a patent, and with what claims? | Before drafting and filing; before any public disclosure | All prior art: patents and applications worldwide, plus non-patent literature | Any age, in force or not | Closest documents, feature matrix, view on claim scope |
| Freedom to operate (clearance) | Can I make and sell this product here without infringing? | Before launch, entering a new market, or investing in a product | Claims of patents and pending applications in the countries you operate in | In force or pending only | Risk-ranked patent list, claim charts, options; opinion if needed |
| Invalidity / validity | Should this granted patent have been granted? | When sued or threatened; before IPR, EPO opposition or UPC revocation; before buying or asserting a patent | Prior art older than the patent's effective date, patents and NPL, standards, products | Any age; targets one in-force patent | Ranked references and invalidity claim charts |
| Landscape / state of the art | Who is doing what in this field, and where are the gaps? | R&D planning, market entry, partner or acquisition screening | All patent families in a defined technology area | All, with status as one dimension | Dataset, charts of trends, players and countries, written analysis |
Patentability search
The question is whether your invention is new and not obvious over everything made public before your filing date, anywhere in the world (35 U.S.C. 102, Art. 54 EPC). Old, expired and abandoned documents all count. The key timing difference between the US and Europe is the grace period: the US excepts the inventor's own disclosures in the year before filing, while the EPO only excuses evident abuse and certain exhibitions within 6 months (Art. 55 EPC). Search before you disclose. Read the patentability search guide.
Freedom-to-operate search
The question flips: not whether you can get a patent, but whether someone else's patent stops you. Infringement is territorial and measured against claims, so the search covers only patents and applications that are or may become in force in the countries where you make, use, sell or import (35 U.S.C. 271(a), Art. 64 EPC). In Europe that includes checking whether a European patent is validated, unitary, and opted out of the Unified Patent Court. Read the freedom-to-operate guide.
Invalidity and validity searches
These aim at one granted patent. An accused infringer looks for art to knock out the claims; a patent owner runs the same search on its own patent, as a validity search, before asserting, licensing or selling it. The forum shapes the search: an IPR at the PTAB accepts only patents and printed publications (35 U.S.C. 311(b)), a post-grant review must be filed within 9 months of grant (321(c)), and an EPO opposition within 9 months of the mention of grant (Art. 99 EPC). Read the invalidity search guide.
Landscape and state-of-the-art searches
These map a field rather than answering a legal question. A state-of-the-art search collects and summarizes the most relevant documents; a landscape adds a cleaned dataset of patent families and statistics on trends, applicants and countries. Remember that applications publish about 18 months after priority (35 U.S.C. 122(b), Art. 93 EPC), so the most recent years always look thin, a point WIPO's landscape guidelines make too. Read the landscape analysis guide.
Searching by office
Every type above usually needs documents from more than one office. For US documents, see USPTO patent search; for European applications and patents, European patent search; and for India, Indian patent search. Each page explains what the office's own databases offer and how our search compares.
Tools for running the search
Whatever the type, the mechanics are the same: pick the right databases, combine keyword and classification queries, and record what you searched so the results can be repeated and checked. The free office databases are the usual starting point. Our walkthrough of USPTO Patent Public Search covers the full-text US collection and its query syntax.
For worldwide coverage, with more than 160 million patent documents, see how to search Espacenet. Google Patents is quicker for a first look and has machine translations built in; our Google Patents search guide covers its operators and where it falls short.
Keywords alone miss documents that use different words for the same thing, so add classification codes from the Cooperative Patent Classification and combine both with Boolean, proximity and truncation operators.
If you run searches often, our comparison of patent search software, free and paid sets out what each tool covers.
Where PatentAssist helps
PatentAssist's prior art search runs one search across USPTO, EPO and IP India records, with an AI agent that takes a plain-language description or classic field search by class, applicant and date. It is strongest for the patent side of patentability searches, where the drafting app also produces an editable patentability report, and for finding candidate documents in FTO and invalidity work. It does not search non-patent literature, check US or European legal status, or give legal opinions.
More patent guides
- Patent drawing requirements: USPTO, EPO and India
37 CFR 1.84, the EPO rules that replaced Rule 46 EPC, and Indian rule 15, compared side by side.
- How to write patent claims: USPTO, EPO and India
Claim structure and worked examples, then the claim rules and fees at the USPTO, the EPO and the Indian Patent Office, side by side.
- Patentability search: how to check novelty before you file
What counts as prior art under 35 U.S.C. 102 and Art. 54 EPC, the grace period gap, search steps and how to read results.
- Freedom-to-operate search in the US and Europe
In-force claims only, legal status checks at the USPTO, EPO and UPC, FTO opinions after Halo, and design-arounds.
- Invalidity search: prior art to challenge a patent
IPR, PGR, EPO opposition and UPC revocation deadlines, prior art dates, standards documents and claim charts.
- Patent landscape analysis, step by step
Building a CPC and keyword dataset, cleaning families and names, the metrics that matter and the 18-month publication lag.
- Google Patents search guide
Search operators and fields, Boolean and proximity syntax, non-patent literature, and where Google Patents falls short of the official databases.
- The Cooperative Patent Classification (CPC), explained
How CPC symbols are built, CPC against IPC, the Y section, how to find the right class and how to search it in each database.
- Patent search Boolean operators and search strings
Boolean, proximity and truncation syntax compared across Patent Public Search, Espacenet, Google Patents and The Lens, with semantic search for contrast.
- The PCT application: timeline, fees and national phase
The international phase month by month, receiving Office and ISA fees in CHF, USD and EUR, national phase deadlines by office, and a deadline calculator.
- How much does a patent cost?
USPTO fees by entity size from filing to the last maintenance fee, what drives professional fees, EPO fees, and an estimator.
- How long does a patent last?
US utility and design terms, patent term adjustment and extension, terminal disclaimers, maintenance fee deadlines, Europe and India, with an expiry estimator.
- Can AI write a patent application?
What AI drafting does well and badly, the USPTO and EPO positions on AI tools, AI inventorship after 2025, and confidentiality.
Types of patent searches: frequently asked questions
What are the main types of patent searches?
Four cover most needs: a patentability (novelty) search before filing, a freedom-to-operate (clearance) search before launching a product, an invalidity or validity search against a granted patent, and a landscape or state-of-the-art search to understand a whole field.
What is the difference between a patentability search and a freedom-to-operate search?
A patentability search asks whether your invention is new and inventive, and looks at all prior art regardless of age or legal status. A freedom-to-operate search asks whether your product infringes someone else's rights, and looks only at the claims of in-force patents and pending applications in the countries where you operate. A patent of your own does not give you freedom to operate.
Is a prior art search the same as a patentability search?
Prior art search is the general term for searching earlier disclosures. A patentability search and an invalidity search are both prior art searches; the first is about your invention before filing, the second about someone else's granted patent. A freedom-to-operate search is not a prior art search: it is a search of in-force claims.
Which patent search should a startup do first?
It depends on the decision in front of you. Before spending on a patent application, a patentability search. Before launching a product or raising money on it, a freedom-to-operate search in your main markets. A landscape helps earlier, when choosing what to build. Many startups start with a quick patentability search on the core idea and add FTO as the product design settles.
Can I do these searches myself?
You can do a useful first pass of a patentability or state-of-the-art search with free tools such as Espacenet, USPTO Patent Public Search and AI search tools. Freedom-to-operate and invalidity work end in legal judgments about claim scope and validity, so have a patent attorney review the results before you rely on them.
Sources: 35 U.S.C. 102, 122, 271, 311 and 321; EPC Articles 54, 55, 64, 93 and 99; Agreement on a Unified Patent Court; WIPO, Guidelines for Preparing Patent Landscape Reports. This guide is general information, not legal advice.