Patent drawing rules are the formal standards that the United States Patent and Trademark Office (USPTO) applies to the drawings filed with a patent application. Most of them sit in 37 CFR 1.84, which fixes the sheet format, the views and the numbering. Under 35 U.S.C. 113, a drawing is required where one is necessary for understanding the subject matter to be patented.
This guide sets out the rules as a checklist and explains why patent drawings that look correct are still objected to.
Patent drawing rules checklist under 37 CFR 1.84
Sheets and margins: 1.84(e), (f) and (g)
All sheets in an application are the same size, A4 or US letter, with a short side at the top and only one side used.
| Requirement | A4 sheet | US letter sheet |
|---|---|---|
| Sheet size | 21.0 cm by 29.7 cm | 21.6 cm by 27.9 cm |
| Top and left margins, at least | 2.5 cm | 2.5 cm |
| Right and bottom margins, at least | 1.5 cm and 1.0 cm | 1.5 cm and 1.0 cm |
Lines, views and scale: 1.84(a), (h), (k) and (l)
Drawings are normally in black and white, with clean, solid black lines that reproduce well. The drawing contains as many views as are needed to show the invention:
- views are grouped, clearly separated and do not overlap;
- views are not joined by projection lines and contain no centre lines;
- a sectional view is hatched with evenly spaced oblique parallel lines.
The scale is large enough for the drawing to stay clear when it is reduced to two-thirds of its size, and notes such as “actual size” are not permitted.
Reference characters and numbering: 1.84(p), (q), (t) and (u)
Reference characters are at least 0.32 cm (1/8 inch) high, carry no brackets or circles and each has a short lead line. The same part carries the same character in every view, and every character in the drawings is mentioned in the description, and the reverse.
Sheets are numbered in the form 2/7 at the top centre, and views as FIG. 1, FIG. 2 and so on, with FIG. 3A for a partial view.
Colour drawings
In a utility application, the USPTO accepts colour drawings only after it grants a petition that explains why colour is necessary. The petition fee under 37 CFR 1.17(h) is USD 150, or USD 60 for a small entity and USD 30 for a micro entity (USPTO fee schedule, checked in October 2026).
Patent drawing requirements that depend on the claims
Under 37 CFR 1.83(a), the drawing must show every feature of the invention that the claims specify, although a conventional feature can be shown as a symbol or a labelled box. The reference characters must also match the description in both directions. A missing feature is hard to repair later, because no amendment may introduce new matter.
Why filed drawings deviate from the patent drawing rules
In Synoptic IP’s experience, most drawing defects trace back to how the drawings were prepared. Drawings are often made by an illustrator whose training is in drawing alone, working from sketches or computer-aided design (CAD) files without seeing the claims or the final description. The defects that follow include:
- a claimed feature that appears in no figure;
- a reference character used for one part in the description and for another in the drawing.
An illustrator who works alongside the drafting and research team understands the invention better and sees what each figure has to support. Synoptic IP therefore recommends an illustrator who knows the application, its claims and its specification as well as the drawing standards, and who prepares the utility patent drawings from the draft claims.
The following example is an illustration and does not describe a real project. An illustrator draws a folding hinge from 6 CAD screenshots, but claim 1 recites a detent that no screenshot shows, so the clean sheets still fail 37 CFR 1.83(a).
How the USPTO enforces the patent drawing rules
The Office of Patent Application Processing (OPAP) first checks whether the drawings can be scanned and reproduced, under section 507 of the Manual of Patent Examining Procedure (MPEP), and usually allows 2 months for corrected drawings.
The examiner then compares the claims with the figures, and objections usually arrive in an Office action answered in the response to the Office action.
Design patent drawings follow 37 CFR 1.152 as well. Formal rules also apply to the information disclosure statement, which a separate guide covers.
Patent drawings prepared to the USPTO rules
Synoptic IP prepares utility and design drawings for US applications in line with the patent drawing rules in 37 CFR 1.84. To receive a quote, send us the sketches, the draft claims and the description through our patent drawing and illustration page.
This guide is general information and is not legal advice.
Frequently Asked Questions
Is a drawing required in every US patent application?
No. Under 35 U.S.C. 113, a utility application needs a drawing only where one is necessary for understanding the subject matter to be patented. A design application is the exception, because it always needs a drawing or a photograph of the design.
What paper size is used for USPTO patent drawings?
The patent drawing rules allow 2 sheet sizes: A4 (21.0 cm by 29.7 cm) and US letter (21.6 cm by 27.9 cm). All drawing sheets in one application must be the same size, with a short side at the top.
Do patent drawings have to be drawn to scale?
No, a fixed scale is not required. The patent drawing rules ask only for a scale at which the drawing remains clear after it is reduced to two-thirds of its size. Notes such as “actual size” are not permitted on the sheets.
Can hand-drawn patent drawings be filed at the USPTO?
Yes. The patent drawing rules require no particular software or method, only solid black, clean and uniformly thick lines inside the margins that reproduce well. Hand-drawn figures are scanned to PDF for electronic filing, in the same way as any other drawing sheet.
Can patent drawings be corrected after filing?
Yes, a drawing that breaks the patent drawing rules can normally be corrected with sheets labelled “Replacement Sheet” or “New Sheet”. The correction cannot add new matter, so a feature that the application as filed did not disclose cannot be drawn in later.
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