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Patent Searching: Search Engines

This guide supplements other existing guides by emphasizing patent contents and search strategies.

Search Engines

Pros and Cons

Each patent search site has its pros and cons as can be seen in Table 1. For the most complete and current search of US Patents, we recommend using the USPTO site. Likewise, for the most complete and current search of European Patents, we recommend using Espacenet. If patent wrappers are desired, those are available from the USPTO and Espacenet sites.

Table 1: Comparison of Patent Search Sites
Site US Pats/Apps NonUS Pats/Apps Other Pat, App (Full) None US Pat Wrapper Pat, App (Full-) Pat, App (Europe+) Wrapper (Dossier) Pat, App (Full-) Pat, App (International-) Not Guaranteed
Scopus Pat, App (Full-) Pat, App (International-) Links to USPTO, Espacenet
Key minus (-) symbol = some patents or applications lacking
plus (+) symbol = additional regions


Google Patents, on the other hand, does offer the convenience of one-stop searching of a broad set of sources. Espacenet offers similar convenience of searching for US and European patents. The USPTO site is the least feature-rich search engine. Historically, this was done deliberately to avoid competition with commercial search engines, although current search features are more user-friendly. Several commercial databases also include provisions for searching patents, but they generally link out to the USPTO and Espacenet sites.  So, it comes down to how you value convenience vs completeness, and what kind of special information you may want.


Links to Search Engines


Patents  Seal of United States Patent and Trademark Office  

Wrapper  Seal of United States Patent and Trademark Office

International Sites

Espacenet      Logo for European Patent Office



Commercial Databases

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