How to search Espacenet

Smart search and Advanced search

Espacenet opens on a single Smart search box. Type a few words and it runs a broad search; type field identifiers and operators and it runs exactly what you wrote. The EPO has synchronised Smart search and Advanced search, so the same query can be built either way.

Advanced search opens a predefined template with one row per criterion (title, abstract, claims, applicant, CPC, publication date and so on). Each row has a drop-down of field operators: any, all, proximity and =. The EPO's note on field operators explains that "all" behaves like AND between the words in the row, "any" like OR, and "=" requires the exact phrase. You cannot type AND, OR or NOT inside an Advanced search field, and rows are combined with the AND/OR selector above them.

In practice, build in Advanced search while you learn the fields, then watch the query appear in the Smart search bar and edit it there. For long queries, the Smart search editor (the rectangle icon in the search bar) gives you a larger box. A query can hold up to 500 search terms, limited also by the URL length your browser supports.

Field identifiers

These are the Smart search identifiers listed in the EPO's Espacenet pocket guide. Quote any value with a space in it.

ctxt is the one to learn first. Title, abstract and claims together are where an invention is actually defined, so a ctxt search is tighter than full text and much wider than title alone. Use ftxt when you need the description too, accepting more noise.

Two number tricks: num= searches publication, application and priority numbers at once, which saves guessing which one you were given, and pn=<country><kind code> searches by kind code. European patents with unitary effect carry the marker C0, so pn=EPC0 finds Unitary Patents (see our Unitary Patent guide).

Boolean and comparison operators

AND, OR and NOT work as you would expect: pa=bosch AND pa=siemens finds joint filings, ctxt=laser NOT ctxt=semiconductor excludes a field. AND is the default between terms. The catch is precedence: Espacenet reads Boolean operators from left to right, so use parentheses whenever you mix AND and OR. (mouse OR rat) AND trap means what it says; without the brackets, you are relying on the order you typed. Nested brackets are read from the innermost out.

Proximity: prox/distance and prox/unit

Espacenet writes proximity differently from the USPTO and most commercial tools. Note the strict "less than": prox/distance<3 means fewer than three words apart.

To keep a proximity search inside one field, put it in brackets after the identifier, the same way the pocket guide scopes classification symbols: ctxt=(calibrat* prox/distance<5 lidar). The pocket guide also uses prox/unit=sentence to tie a classification to the office that assigned it: cpc=(C08F220/38 prox/unit=sentence (EP)) finds documents where the EPO gave that symbol. That matters because the same family can be classified differently by different offices.

Truncation and dates

The restrictions are strict. Left truncation (?car) is not supported. A * needs at least three characters in front of it. With two characters before a ? or #, you can use at most three of them; with three or more characters, at most seven. And wildcards cannot be used on IPC or CPC symbols at all.

Dates accept most formats you would type: 2019, 201903, 20190305, 2019-03-05 or 05.03.2019 all work. For ranges, pd within "1998 2018", pd within "1998:2018" and pd="199801:201812" are equivalent styles. One trap: pd searches the date of the earliest publication of a document (the A publication), not later ones such as the B grant, because later publication dates are not indexed for search.

Searching by CPC, and the /low operator

The Cooperative Patent Classification is run jointly by the EPO and the USPTO and has around 250,000 entries, according to the EPO. It is the most reliable way to sweep a technical field in Espacenet, because it does not depend on the words a drafter chose or the language they wrote in.

• Write symbols without spaces: cpc=G01S17/931. Use cl= to search IPC and CPC together, and cpcc= for combination sets in chemistry.
• Classification data is auto-posted up to group level, so a search on a main group also finds everything classified below it.
• At subgroup level, add /low to include the lower subgroups: cpc=B65D81/24/low also finds B65D81/26. With /low you must use the = operator and only one symbol per field.
• Not sure of the symbol? The Classification search tab lets you search the scheme by keyword and send symbols straight to your query, and since July 2024 Espacenet links to the EPO's AI-driven CPC text categoriser, which suggests symbols from a plain-language description.

Our CPC classification guide explains how to read a symbol and pick the right level.

Worked examples

The first three build a search for a method of recalibrating a vehicle lidar. The last is the EPO's own multilingual example.

1. ctxt=(calibrat* prox/distance<5 lidar)

   Calibration and lidar within a few words of each other in the title, abstract or claims.

2. cpc=G01S7/497/low

   CPC G01S 7/497, means for monitoring or calibrating lidar-type systems, plus every subgroup below it such as 7/4972 (alignment of sensor).

3. ctxt=(calibrat* prox/distance<5 lidar) AND cpc=G01S7/497/low AND pd within "2015 2025"

   The two combined and limited to publications from 2015 to 2025. Remember that pd searches the earliest publication of each document.

4. (spectacle?? or lunette? or Brille?) and (hollow or creu??? or hohl??) and transpar*

   The EPO's own pocket-guide example: one concept in English, French and German, the three searchable languages, with truncation for plurals and inflections.

The EPO uses the last example to show why filters matter. Run it, then filter by publication date up to 1 January 2017. At publication level, a Spanish utility model published in February 2016 drops out: it is in Spanish, so it does not match the keywords. At family level it stays in, because a later WO family member matches the English keywords and the Spanish member matches the date. The family as a whole meets both criteria. Since May 2023 the filter toggle defaults to family level, which is the right setting for prior art.

Families, legal events and Global Dossier

Open a result and the record has several views. The ones that save the most time:

• INPADOC patent family. The extended family groups every document that shares at least one priority with another member, directly or indirectly. It is wider than the simple family (exactly the same priorities) and is how you find the US, Japanese or Chinese counterpart of a European filing, or a continuation-in-part.
• Legal events. The view formerly called "INPADOC legal status" lists events reported by offices: grant, lapse, renewal fee payments, oppositions. The Patent family tab also shows the latest legal events across the whole family. These are events, not an official status; check the European Patent Register and national registers before you rely on whether a patent is in force.
• Global Dossier. A link on the record opens the file wrapper where the office makes it available. The EPO lists the participating offices as CIPO (Canada), CNIPA (China), the EPO, JPO (Japan), KIPO (Korea), the USPTO and WIPO, with English machine translations of Chinese, Japanese and Korean documents. This is how you read the examiner's objections in the other offices.
• Citations. Cited and citing documents, including non-patent literature, with the option to move them into your result list. ct= searches citations directly, and it is the only way to find documents that cite XP non-patent references, which cannot be searched themselves.
• Patent Translate. The EPO's machine translation, built with Google, covers 32 languages to and from English, French and German. Pick the abstract, description or claims, choose a language, and hover to see the original sentence by sentence.

Saving, exporting and limits

Star documents to keep them in My patents, and download result lists as xlsx or csv files. The result count is exact. Know the limits too. Only English, German and French are searchable as original text, though Espacenet also indexes English machine translations of many other documents, with coverage that varies by language. XP documents cannot be searched. Robots and bulk downloads are blocked; use Open Patent Services for automated access. And like every keyword database, Espacenet returns what matches your words, not what matches your idea.

Searching US documents in depth? The USPTO's own tool has richer US-specific fields; see our Patent Public Search guide. For how Espacenet's syntax compares with Google Patents and The Lens, see patent search Boolean operators, and for a broad first pass with non-patent literature, our Google Patents guide.

More EPO guides

• How to file a European patent application

  Direct or Euro-PCT filing, search, examination, grant and validation, with the EPO fees in force from 1 April 2026.

• 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.

• The Unitary Patent and the UPC, explained

  The 18 countries covered, renewal fees, the UPC opt-out, and when classic validation is the better choice.

• EPO fees 2026: the full fee schedule

  Every EPO fee in force from 1 April 2026, the 30% micro-entity reduction, PCT fees at the EPO and a fee calculator.

• How much does a European patent cost?

  EPO fees to grant, translations, validation and renewals, with the EPO's Unitary Patent cost comparison and two worked examples.

• European patent validation: countries and deadlines

  Translation rules and deadlines in all 40 EPC states, the London Agreement, extension and validation states, and the Unitary Patent.

• The problem-solution approach to inventive step at the EPO

  Closest prior art, the objective technical problem and the could-would test, with a fully worked example and the usual mistakes.

• Software and AI patents in Europe

  Computer-implemented and AI inventions at the EPO: Article 52, COMVIK, G 1/19, claim drafting, and the UK and US positions.

• European patent opposition at the EPO

  The 9-month deadline and fee, the grounds, procedure and oral proceedings, appeal to the Boards, and how it compares with UPC revocation.

• Supplementary protection certificates (SPCs) in Europe

  Who can get an SPC, how long it lasts, the filing deadline, the paediatric extension, the manufacturing waiver and the unitary SPC proposal.

• The European search report and EESR, explained

  X, Y and A citation categories, the search opinion, Rule 62a and 63 limited searches, and the Rule 70a deadline to reply.

• Entering the European phase from a PCT application

  The 31-month deadline, Rule 159 acts and fees, the supplementary search, Rule 161, translations and a worked example.

• European divisional applications under Rule 36 EPC

  When the parent is pending, fees by generation, back renewal fees, the Article 76 added-matter trap and timing.

• How to speed up EPO prosecution: PACE, PPH and waivers

  PACE since February 2026, the Rule 70(2) and Rule 161 waivers, PPH with the USPTO, and fast Rule 71(3) approval.

• The European Patent Convention, annotated

  Key EPC Articles and Rules explained one by one, from novelty and claims to Rule 71(3), with deadlines, fees and Enlarged Board case law.

• Types of patent searches, and which one you need

  Patentability, freedom-to-operate, invalidity and landscape searches compared by purpose, timing, scope and deliverable.

• 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.

All guides, by patent office