Article 50

EUROPEAN PATENT OFFICE

Information from the EPO

Definition of "DOCX" for filing with the European Patent Office (version 2) dated 7 July 2025

This definition of "DOCX" supersedes the definition of "DOCX" under Article 4 of the decision of the Vice-President Legal and International Affairs of the European Patent Office (Directorate-General 5) dated 21 April 2020 concerning the conditions for participating in the pilot project for Online Filing 2.0, as published in the OJ EPO 2020, A45.

It will enter into force on 1 October 2025 and apply to filings made as part of the pilot project for DOCX filing in Online Filing 2.0.

Office Open XML (DOCX OOXML)

All documents in Office Open XML format (DOCX OOXML), which are represented by the file extension ".docx", must conform to the DOCX mark-up strict variant of OOXML specified in the "word processing" category of ISO/IEC 29500-1:2008. In addition, valid DOCX OOXML documents must fulfil the requirements laid down below.

1. Application document

All documents in DOCX OOXML format must meet the following requirements:

(a) Be in the format Office Open XML marked up according to the strict variant of OOXML for the category "word processing" (ISO/IEC 29500-1:2008);

(b) DOCX file must not be encrypted;

(c) Page size must be either letter or A4;

(d) In accordance with Rule 49(2) EPC and the decision of the President of the European Patent Office adopted thereunder,1 the font size 11 is recommended for plain text within the application document;

(e) The headings and sections within the application document should adhere to the Common Application Format (CAF) standard (see wipo.int/pct/en/filing/caf_example.html) and use a paragraph style that adheres to the Office Open XML naming standards, as follows:

• Titles of the main sections of the application as specified in "Application headings and sections" below
• Description sub-sections as specified in "Application headings and sections" below
• Claim lists as specified in "Application headings and sections" below
• Figure lists as specified in "Application headings and sections" below (where applicable)
• Reference numbers
• Patent and non-patent citations
• Bio-deposit
• Citation list;

(f) No hidden text;

(g) No annotations (e.g. comments, ink annotations, etc.);

(h) No tracked changes;

(i) The following OLE objects are supported:

• ChemDraw.Document.6.0
• MDLDrawOLE.MDLDrawObject.1
• ISISServer
• Equation.3
• Enhance.Map
• Visio.Drawing.11
• Equation.DSMT4
• ChemWindow.Document
• Origin50.Graph
• PatXML.Image
• Prism6.Document
• ACD.ChemSketch.20
• Visio.Drawing.15
• Prism5.Document
• ChemDraw.Document.4.5
• SolidEdge.DraftDocument
• Word.Picture.8;

(j) Embedded images must be in TIFF, JPEG (JFIF) or PNG format;

(k) Maximum allowable size for a single embedded image is 1 Mb;

(l) No automatic updating of bookmarked or cross-referenced content, i.e. it is retrieved as submitted;

(m) No text extraction from headers and footers;

(n) No watermarks;

(o) No content controls;

(p) Typographical text highlighting effects are limited to the ones defined in the "application-body.dtd" (Appendix I of the Annex F to the Administrative Instructions under the PCT) (e.g. underlining, bold, italic, etc.);

(q) All text in the document must be typed using the following supported Unicode fonts:

• Arial
• Arial Black
• Arial Narrow
• Arial Rounded MT Bold
• Arial Unicode MR Regular
• Batang
• Calibri
• Cambria
• Cambria Math
• Courier New
• Courier Regular
• Georgia
• MS Mincho
• PMingLiU
• SimSun
• Symbol
• Tahoma
• Times New Roman
• Trebuchet MS
• Verdana

(r) No duplication of application headings;

(s) No hyperlinks.

2. Application headings and sections

Headings and sections are used to divide the application body into different subject parts. The headings are defined as main sections (abstract, description, claims, drawings). The headings and sections of the application, including the order in which they appear, should follow the CAF guidelines (see example at wipo.int/pct/en/filing/caf_example.html). For an application written in English, the following applies:

2.1 Headings of the application body:

• Description
• Claims (mandatory)
• Abstract (mandatory)
• Drawings (where applicable)

Each heading of the application body (description, claim, abstract and, where applicable, drawings) must be at the top of a new page, separated either in a new section (page break) or separated by a page break, both functionalities being available in DOCX OOXML format.

2.2 Sections and sub-sections in a description (recommended):

Title of invention or Title

Technical field or Field

Background art or Background

Summary of invention or Summary

• Technical problem
• Solution to problem
• Advantageous effects of invention

(Brief description of drawings)

Description of embodiments

Examples

• Industrial applicability
• Reference signs list
• Reference to deposited biological material
• (Sequence-listing free text)
• Citation list

Patent literature

Non-patent literature

2.3 Numbering of claims

The set of claims must be numbered sequentially. It is recommended to use the automatic numbering function of the DOCX editor. If the claims are numbered manually, one of the following two formats should be used:

Claim 1.

Claim 2.

to

Claim N.

or

[Claim 1]

[Claim 2]

to

[Claim N]

2.4 Drawings

Drawings (mandatory where drawings are present in the application and not filed separately in PDF in accordance with section 3):

The figures must be listed in numbered sequence, as follows:

Fig. 1

Fig. 2

to

Fig. N

3. Drawings filed separately in PDF

Any drawings may also be filed as a separate document in PDF instead of DOCX.2 Drawings filed separately in PDF must comply with Annex F to the Administrative Instructions under the PCT.