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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. The decision of which search engine to use comes down to how you value convenience vs completeness, and what kind of special information you may want.  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 through 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)
PatentScope Pat, App (Full-) Pat, App (International-) US updated weekly Pat, App (Full-) Pat, App (International-) Currency 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 searching a broad set of sources from different countries. Espacenet and PatentScope offer similar convenience of searching for patents from multiple countries.  From any of these three sources, new patents from regions outside their main focus areas may not appear in their databases immediately. Several commercial databases also include provisions for searching the patent literature. 


*We note that the USPTO search engine has recently been updated, and offers several advanced search features, including proximity searching (e.g., finding documents where keywords are within a specified distance from each other) and external searches (queries run via a URL).

Links to Search Engines


Patents & Applications  Seal of United States Patent and Trademark Office  

File Wrapper  Seal of United States Patent and Trademark Office

International Sites

EspacenetLogo for European Patent Office




Commercial Databases