devcat
September 24, 2026
You’ve done the hard part. Your claims are ready. Now it’s time to submit your patent drawings to the European Patent Office. But before you upload that final set, there’s one thing you need to know.
The EPO has very specific rules about how drawings must be presented. From margins and figure labels to line quality and text placement, every detail is governed by strict formatting requirements laid out in the EPO Guidelines for Formalities Examination.
Getting even one of those details wrong can trigger formal objections. That means delays, added cost, or even rejection if the issue is not fixed in time.
Understanding EPO patent drawing requirements is essential for anyone filing in Europe. Whether you’re an inventor, patent drafter, or attorney, the rules are clear. And that’s exactly what this article is here to help you with.
We break down the latest EPO patent drawing rules for 2025 in plain terms. Without the legal jargon. Just all the information you need to get your drawings accepted the first time.
Recommended Read: Looking for tools that simplify compliance with EPO patent drawing requirements? Check out our expert-curated list of patent drawing software for 2025.
When filing a utility or design patent application with the European Patent Office, drawing compliance is non-negotiable. The EPO has its own formal standards that go beyond basic formatting. These standards apply whether you’re filing directly in Europe or entering through the PCT regional phase.
This section outlines the core EPO rules around when drawings are needed, which types are accepted, and what formatting requirements must be followed. We’ll also cover the official sheet size, usable area, margin requirements, numbering of figures and sheets, and placement of text, as detailed in the EPO Guidelines.
And if you’re coming in through the PCT route, take note: drawings that passed during the international phase may still face objections during European entry. The EPO applies its own standards, and non-compliant figures can lead to costly delays or corrections.
Patent drawings are not always required, but when they are, they must meet strict formal standards under EPO guidelines. This section explains when drawings are necessary, whether optional illustrations can be included, and how EPO treats such material during examination.
Q1. Are patent drawings always required when filing with the EPO?
No. Under EPO rules, drawings are only required when they are necessary to understand the invention. If the invention can be clearly explained through the written description and claims alone, drawings are optional. However, if the specification refers to drawings, they must be included at the time of filing.
Q2. Can applicants include drawings even if they are not strictly necessary?
Yes. Applicants may submit drawings to clarify or illustrate the invention, even when they are not required. As long as the drawings comply with formal standards, the EPO accepts optional illustrations if they support the disclosure.
Q3. Can a patent office later require drawings that were not submitted initially?
Yes. If an examiner at the EPO finds that drawings are essential to understanding the invention, they may request that the applicant supply them within two months. This typically occurs during the formalities check or in response to a communication under Rule 58 EPC.
Q4. Shall flow sheets and diagrams be considered drawings?
Yes. Under EPO practice, flow sheets, block diagrams, and similar graphic representations are treated as formal drawings. They must meet the same presentation standards as technical illustrations and are subject to the same formatting rules.
Q5. What time limit shall apply if a designated office requires drawings?
When the EPO requires missing drawings that were not originally filed, it typically sets a two-month period to correct the deficiency. This is consistent with the procedural safeguards in the European phase and aligns with the principles outlined in the PCT and EPO implementing rules.
Q6. Are new drawings required in the national phase if PCT Rule 11 was followed?
Not necessarily. If the drawings submitted during the international phase comply with PCT Rule 11 and are acceptable under EPO standards, they may be retained in the European phase. However, the EPO may request updated or replacement drawings if the originals do not meet formal EPO requirements.
Q7. Can an entire missing sheet of drawings be corrected later?
Yes, but only under strict conditions. If an entire sheet of drawings was mistakenly omitted at filing, you can add it within two months of filing only if it is completely contained in the priority document and a priority claim is present on the filing date.
This incorporation under Rule 56a EPC preserves the original filing date. Otherwise, adding the sheet later resets the filing date to the date of addition.
Q8. Are rectifications of obvious mistakes in drawings considered amendments? No. If an error in the drawings is obvious, meaning a skilled reader immediately sees the mistake and knows the intended correction, it can be corrected under Rule 139 EPC without being treated as an amendment.
Q9. When can drawings be amended in the patent process?
Drawings can be amended at any time during prosecution if:
All amendments must be “obvious corrections” or within the original disclosure. Disclosure of new matter is not allowed.
Q10. What should an examiner do if referenced drawings are missing from the search copy file?
EPO examiners are not expected to pursue missing drawing content themselves. If drawings are missing from the published grant text (e.g. B1 format), the EPO issues an error correction communication (under Rule 140 EPC). The responsibility to ensure drawings are present rests with the applicant, even after publication.
Patent drawings filed with the EPO must follow specific physical formatting rules. This section explains the sheet size, usable area, and margin standards as enforced by Chapter IX of the EPO Guidelines.
Q11. What sheet size is required for patent drawings under the EPO?
Drawings must be submitted on A4 paper measuring 29.7 cm by 21.0 cm. The sheets must be white, strong, smooth, matt, and durable, with a recommended paper weight between 80 and 120 g/m². Only one side of each sheet may be used, and all sheets must be free from cracks, folds, creases, or alterations.
Q12. What is the maximum usable surface area for drawings on each sheet?
The usable drawing area cannot exceed 26.2 cm × 17.0 cm.
Q13. Are frames allowed around the usable surface on drawing sheets?
No. Sheets must not include any frames around the usable surface. Drawings should start and end within the permitted margins.
Q14. What are the minimum margins for drawings?
The standard minimum margins are:
These margins ensure proper printing and binding without obscuring the drawing content.
This section explains how drawings must be formatted. It also includes details on where to include them, how to number sheets and figures, and how to present multiple figures per sheet to meet EPO standards and avoid common objections.
Q15. Where shall drawings be included in the application?
Drawings must be submitted on separate sheets, not embedded in the description, claims, or abstract. They form a distinct part of the application and must stand alone.
Q16. How shall drawing sheets be numbered?
Each sheet of drawings must be numbered using consecutive Arabic numerals, placed centered at the top of the sheet, but within the usable drawing area, not in the margin. The font should be larger than reference sign numbers to prevent confusion.
Q17. What format shall be used for drawing sheet numbers?
The EPO prefers a separate numbering series for drawings, starting at drawing #1. However, applicants can also number all parts of the application—including description, claims, abstract, and drawings—in a single continuous series, starting from the first page of the description.
Q18. How shall figures within the drawings be numbered?
Figures must be numbered in Arabic numerals, independent of sheet numbers, and always preceded by “FIG”. If there is only one figure, one need not number it or use “FIG”.
For figures split into parts, labels like FIG 5A, FIG 5B can be used. Numbers must be clear, simple, and not enclosed in brackets, circles, or quotes. They should also be larger than reference signs.
Patent drawings at the EPO must be almost entirely free of text, except in very specific and minimal cases. This section clarifies which words are allowed, when they’re necessary, and how they must be positioned.
Q19. Shall text be allowed in patent drawings?
No, text is not allowed in EPO drawings unless absolutely indispensable. Only a single word or a few words may be used when needed to understand the drawing. Examples include “water,” “steam,” “section on AB,” or functional terms in flowcharts like “controller” or “memory unit.”
In flowcharts or block diagrams, short descriptive phrases may be accepted if graphical elements alone are not enough to convey meaning. However, all text must be kept to the minimum necessary.
Q20. How shall any indispensable words be placed within the drawings?
Any permitted text must be placed with enough clear space around it so that it can be translated and replaced without affecting the drawing. The text should never touch or overlap drawing lines, and should always appear separate from graphical elements.
This section outlines specific technical standards for EPO patent drawings, including line execution, cross‐section hatching, scaling, and proper use of symbols and signs.
Q21. How shall lines and strokes in drawings be executed?
Lines must be black, durable, and uniformly thick, with legibility suitable for electronic or photographic reproduction. All lines must be drawn using drafting instruments or CAD tools, except for irregular shapes where no instrument exists. Colour drawings can be submitted but should be be scanned, printed and made available for file inspection in black and white only.
Q22. How shall cross-sections be indicated in drawings?
Cross-sections must be shown using regular hatching lines, spaced based on the size of the area. The hatching should never block reference signs or leader lines and can be interrupted to keep those signs clear. The figure where the cut is taken should clearly show the section line, using labels like “Section on AB” or Roman numerals at each end of the line that match the figure showing the section.
Q23. What graphical standard shall drawings meet for scale and reproduction?
Drawings must remain legible when reduced to two-thirds their original size. If details are lost at that scale, the figure must be redrawn larger or split into multiple parts.
Q24. How shall the scale be shown when used?
Scales must be shown graphically (e.g., bar scales). Text like “actual size” or “½ scale” is not allowed on drawings or in the description.
Q25. How shall numbers, letters, and reference signs appear in drawings?
All numbers, letters, and reference signs must be simple, clear, and not enclosed in brackets, circles, or quotation marks. They should be larger than the text in reference signs, aligned with the drawing’s orientation, and placed near the corresponding part without cluttering.
Q26. Shall lines be hand‑drawn or drawn using drafting instruments?
All drawings must be produced using drafting instruments or CAD tools. Freehand drawing is only acceptable for irregular shapes that cannot be instrument-drawn.
Q27. What is the minimum height for letters and numbers in drawings?
All letters and numbers on the drawings must be at least 0.32 cm (3.2 mm) tall. Only Latin letters and, if necessary, Greek letters are allowed.
Q28. Must reference signs be consistent throughout the application?
Absolutely. Any reference sign used in a drawing must also appear in the description or claims, and vice versa. Using the same sign for the same feature across all drawings is mandatory. Omissions or inconsistencies can lead to formal objections.
Q29. What if the text in drawings is not in an accepted language?
If you include text in the drawings that isn’t in English, French, or German, the EPO will require you to translate it into one of these official languages, typically under Rule 159 EPC. You must provide the translation before entry into the European phase to proceed smoothly.
Q30. Can several figures appear on one drawing sheet?
Yes. You may include multiple figures on the same sheet. If those partial figures form a complete figure across sheets, they must be arranged so they can be aligned edge-to-edge without overlap and with a clear reference layout.
Q31. How shall the figures be arranged on the sheet?
Figures should be neatly separated and arranged “upright” where possible, to maximize space and legibility. If space constraints force rotation, the top of the figure must be at the top of that sheet’s orientation. The layout must clearly distinguish each view.
Q32. Are photographs allowed instead of drawings?
Yes, in rare cases. Photographs (or their copies) are permitted only when a drawing cannot adequately show the invention, such as for biological samples or microscopic features. They must otherwise meet standard drawing rules: A4 size, black and white reproduction, margins, and must be numbered like drawings. Color photographs are allowed but will be scanned and published in black and white.
These EPO drawing requirements may seem detailed, but getting them right is critical to avoid delays or rejections. But if you’d like expert help, Pinch Patent Drawings can turn your rough sketches into clean, fully EPO-compliant figures without the guesswork.
Patent drawings aren’t just visual aids. They’re legal components of your application.
Whether you’re filing a utility, design, or plant patent, following both PCT and EPO drawing requirements is essential. It ensures your submission is accepted without delays or objections.
At Pinch Patent Drawings, we simplify this process. Our team converts your sketches or CAD files into professionally formatted drawings that meet all international standards. This applies whether you’re filing under the Patent Cooperation Treaty (PCT) or directly with the European Patent Office (EPO).
You don’t need to decode formatting rules from different jurisdictions. We stay current with the latest PCT guidelines and EPO formal drawing rules. Every drawing we deliver is ready for examiner review.
If you’re looking for a faster and more reliable way to handle patent drawings, without risking rejections or searching for a freelance illustrator, we are here to help.
Get your first drawing on the house.
This article is based on official sources from the European Patent Office (EPO), including:
Every effort has been made to simplify the regulatory language and provide accurate, practical interpretations for patent applicants. However, please note that EPO drawing requirements are subject to updates, and their application can vary depending on the specifics of each filing.
This article is intended for informational purposes only and should not be construed as legal advice. For the most up-to-date and case-specific guidance, consult official EPO resources or a qualified European patent professional.
For every innovator, attorney, and team working to protect ideas and file patents faster. We are the only platform that combines speed, compliance, and confidentiality to simplify your patent drawing process.
For every innovator, attorney, and team working to protect ideas and file patents faster. We are the only platform that combines speed, compliance, and confidentiality to simplify your patent drawing process.
