USPTO drawing requirements: 37 CFR 1.84 checklist
For a US utility application, 37 CFR 1.84 asks for drawing sheets of one fixed size — US Letter or A4 — with at least 2.5 cm clear at the top and left, 1.5 cm at the right and 1.0 cm at the bottom, solid black lines, and letters and numerals at least 0.32 cm high. That is the measurable core; the sections below go clause by clause.
Rule text read against the eCFR and MPEP 608.02, checked 2026-11. Not legal advice.
Six points to check first
These are the points to check before you file. Each one can be measured on the printed sheet; select a row for the clause in full.
Paper and margins
§ 1.84(f), (g)US Letter (21.6 × 27.9 cm) or A4 (21.0 × 29.7 cm), the same size for every sheet. Top and left at least 2.5 cm, right at least 1.5 cm, bottom at least 1.0 cm.
Lines and black-and-white
§ 1.84(a)(1), (l)Solid black lines, uniformly thick and dense enough to reproduce. Color in a utility drawing needs an approved petition.
Lettering height
§ 1.84(p)(3)Letters, numerals and reference characters at least 0.32 cm (1/8 inch) high on the printed sheet.
FIG. labels
§ 1.84(u)Views numbered 1, 2, 3 … in order, each preceded by “FIG.” A single view is not numbered and “FIG.” is not used.
Sheet numbers
§ 1.84(t)“1/3”, “2/3” … in the middle of the top, inside the sight and clear of the margin, larger than the reference numerals.
Reference numerals
§ 1.84(p)(4), (p)(5)One numeral per part, the same numeral in every view. Every numeral in the description appears on the sheet, and nothing else does.
Sheet size and margins
Two sheet sizes are allowed, and every sheet in one application must use the same one. The margins leave a usable surface — the sight — that is smaller than the paper.
Sheet sizes
- A4
- 21.0 × 29.7 cm (DIN size A4)Largest sight: 17.0 × 26.2 cm.§ 1.84(f)(1), (g)
- US Letter
- 21.6 × 27.9 cm (8 1/2 × 11 inches)Largest sight: 17.6 × 24.4 cm (6 15/16 × 9 5/8 inches).§ 1.84(f)(2), (g)
Minimum margins
- Topat least 2.5 cm (1 inch)
- Leftat least 2.5 cm (1 inch)
- Rightat least 1.5 cm (5/8 inch)
- Bottomat least 1.0 cm (3/8 inch)
§ 1.84(g)
- All drawing sheets in one application must be the same size, and one of the shorter sides is regarded as the top (1.84(f)).
- The sight is the usable surface. No frame goes around it, but scan target cross-hairs should be printed in two diagonally opposite (catercorner) margin corners (1.84(g)).
- Only one side of the sheet is used. Paper must be flexible, strong, white, smooth, non-shiny and durable, and sheets must be free of alterations, overwritings and interlineations (1.84(e)).
- A drawing is reduced to two-thirds in reproduction, so the scale must stay large enough to show the mechanism without crowding at that size (1.84(k)).
Lines and black-and-white
A utility drawing is assumed to be reproduced in black and white, so the test is whether every line survives printing.
- § 1.84(a)(1)
- Black and white drawings are normally required. India ink, or its equivalent that secures solid black lines, must be used. Color in a utility application is the exception, not the default (see the color and photographs section).
- § 1.84(l)
- Every line, number and letter must be durable, clean, black, sufficiently dense and dark, and uniformly thick and well-defined. Line weights must be heavy enough to reproduce, including fine lines, shading and section lines. Two thicknesses may be used only where they carry different meanings.
- § 1.84(m)
- Solid black shading areas are not permitted, except when used to represent bar graphs or color. Shading must never reduce legibility.
Lettering height and numerals
The number that is easiest to miss is 0.32 cm. It applies to every number, letter and reference character on the sheet, not only to the labels you think of as text.
- § 1.84(p)(3)
- Numbers, letters and reference characters must measure at least 0.32 cm (1/8 inch) in height. They should not be placed where they interfere with the drawing, should not cross or mingle with the lines, and should not sit on hatched or shaded surfaces. Where a character marks a surface or cross section it may be underlined, with a blank left in the hatching so it stays distinct.
- § 1.84(p)(1)
- Reference characters, sheet numbers and view numbers must be plain and legible, not used with brackets or inverted commas, and not enclosed within outlines such as a circle. They must be oriented in the same direction as the view so the sheet does not have to be rotated.
- § 1.84(p)(2)
- Letters use the English alphabet, except where another alphabet is customarily used, such as Greek letters for angles, wavelengths and mathematical formulas.
How the height is measured
The rule states a height but not the metric. We measure capital letters — the tallest glyphs in most labels — on the printed sheet at final scale. Lower-case letters are shorter than capitals, so a label can contain letters below 0.32 cm even when its capitals pass; the check does not measure them separately. The same minimum is applied to reference numerals.
Figure labels and sheet numbers
Views and sheets are numbered for different purposes and must not be confused: view numbers say which figure this is, sheet numbers say where the sheet sits in the set.
- § 1.84(u)(1)
- Views are numbered in consecutive Arabic numerals starting with 1, independent of the sheet numbering, and if possible in the order they appear on the sheet. Each number is preceded by the abbreviation “FIG.”. Partial views that form one complete view carry the same number plus a capital letter, as in FIG. 2A and FIG. 2B. Where an application has only one view, it is not numbered and “FIG.” must not appear.
- § 1.84(u)(2)
- View numbers must be simple and clear, with no brackets, circles or inverted commas, and must be larger than the numbers used for reference characters.
Sheet numbers
Sheets should be numbered with a fraction — sheet number over total number of drawing sheets — inside the sight at the top.
- § 1.84(t)
- Sheets of drawings should be numbered in consecutive Arabic numerals starting with 1, within the sight. If a number is present it must go in the middle of the top of the sheet, never in the margin; it may move to the right-hand side when the drawing reaches too close to the middle of the top edge.
- § 1.84(t)
- The number of each sheet should be shown by two Arabic numerals either side of an oblique line — sheet number first, total number of drawing sheets second — with no other marking. The sheet numbering must be clear and larger than the reference numerals so the two are not confused.
1.84 does not say where on the sheet the “FIG.” label itself sits. Placing it below the view is drafting convention, not rule text.
Reference characters
Reference numerals are the link between the drawing and the description. They fail in two directions: a numeral on the sheet that the description never mentions, and a part the description names that the sheet never numbers.
- § 1.84(p)(4)
- The same part of the invention, wherever it appears, must always carry the same reference character, and one character must never be used for two different parts.
- § 1.84(p)(5)
- A reference character that the description does not mention must not appear on the drawing. Every character mentioned in the description must appear on the drawing. The two lists have to match in both directions.
- § 1.84(q)
- Lead lines run between a reference character and the detail it names. They may be straight or curved and should be as short as possible, must not cross each other, and must be drawn like every other line (1.84(l)). A character that marks a surface or cross section needs no lead line, but must be underlined to show that none was left out by mistake.
Flowcharts and block diagrams
1.84 does not use the words “flowchart” or “block diagram”. The rule applies to every view, whatever it depicts; the layout conventions that make a software figure readable are marked below because they are not in the rule text.
- § 1.84(h)
- The drawing must contain as many views as necessary to show the invention, grouped together and clearly separated, and must not share a sheet with the specification, claims or abstract. Views must not be connected by projection lines and must not contain center lines.
- § 1.84(n), (o)
- Graphical drawing symbols may stand for conventional elements, provided the elements are adequately identified in the specification. Descriptive legends may be used with the Office’s approval, or required by the examiner, and should contain as few words as possible.
- Common practiceNot rule text
- One step per box with arrows for direction, step numerals at the start of the box label, module numerals outside the box on a lead line (1.84(p)(1) says reference characters must not be “enclosed within outlines, e.g., encircled”; the rule does not say how that applies to a numeral inside a flowchart box, so confirm that choice with your attorney), decisions drawn as a box or diamond with two labelled exits, and the “FIG. n” label below the view. The rule text does not prescribe this layout; it is the convention PatentQuill draws to.
Because the rule is silent on layout, the figure stands or falls on clarity and on agreement with the description. PatentQuill draws flowcharts and block diagrams to the conventions above; see the checks it runs. Choosing a tool? The patent drawing software comparison sets out what a patent sheet needs that general drawing apps do not cover.
Color and photographs
Both are exceptions in a utility application. The rule text is short, and the conditions are specific.
- § 1.84(a)(2)
- Color drawings are permitted in design applications. In a utility application they are allowed only on rare occasions, where color is the only practical medium to disclose the subject matter, and only after a petition is granted. The petition carries a fee, the required sets of color drawings, and an amendment adding the standard statement to the specification. Color drawings must still reproduce in black and white in the printed patent.
- § 1.84(b)
- Photographs are not ordinarily permitted in utility or design applications. They are accepted when a photograph is the only practicable medium for illustrating the claimed invention, and must be of sufficient quality that every detail reproduces in the printed patent. Color photographs need both the color and the photograph conditions to be met.
How PatentQuill checks these
The checks run on the final sheet, not on the model behind it, and each one is reported in plain language before export. This is the complete list of what the checks cover.
- Margins§ 1.84(g)
- Every mark, including the FIG. label and the sheet number, must sit inside the printable area measured from the sheet edges.
- Text height§ 1.84(p)(3)
- The smallest capital letter on the sheet is measured against the 0.32 cm minimum at print scale.
- Black lines only§ 1.84(a)(1), (l)
- Any color other than black, any gray fill, transparency or embedded image is listed for removal.
- FIG. labels§ 1.84(u)
- Each view on the sheet needs its own “FIG. n” label in the required form.
- Sheet numbers§ 1.84(t)
- The “n/total” number must be present and centred at the top of each sheet.
- Reference numerals§ 1.84(p)(4), (p)(5)
- Every box must carry a numeral, no numeral may repeat, and the numerals are cross-checked both ways against the text you pasted.
- Fits the sheet§ 1.84(g), (p)(3)
- The drawing must fit the usable area at full size, or be reduced only while capital letters and numerals still measure at least 0.32 cm.
- Text clear of lines§ 1.84(p)(3)
- No line or box outline may run through a label or a reference numeral.
Also checked, as drafting hygiene rather than a 1.84 requirement: no overlapping boxes, no lines hidden under boxes, crossings clear of connections, decisions have two labelled branches.
Passing these checks is not a prediction of acceptance. Whether a figure shows every claimed feature stays the filer’s judgment.
Check a PDF you already have — free, in the browser. The comparison of free patent drawing checker tools covers what each one measures.
Make a method flowchart and make a system block diagram from your own text.
Rule text and where it comes from
Every figure on this page is quoted from the current text of 37 CFR 1.84, with examination guidance in MPEP 608.02.
- 37 CFR 1.84 — Standards for drawings
Electronic Code of Federal Regulations
- MPEP 608.02 — Drawing
USPTO Manual of Patent Examining Procedure
Checked 2026-11. 1.84(y) points to the separate rules for design drawings (1.152), international design reproductions (1.1026), plant drawings (1.165) and reissue drawings (1.173(a)(2)).
Questions
Do I need a particular drawing program?
No. 37 CFR 1.84 regulates the printed sheet, not the software: sheet size, margins, line quality, lettering height, labels and numbering. A CAD file, a drawing app, a generated sheet and a hand-inked sheet are judged on the same printed page, so the question is whether the output meets those measurable rules.
Can patent drawings be hand-drawn?
Yes, if the finished sheet still meets the rules. Black ink, or its equivalent that secures solid black lines, is required (1.84(a)(1)); every line and letter must be durable, clean, black and uniformly thick (1.84(l)); letters and numerals must be at least 0.32 cm high (1.84(p)(3)); corrections must be durable and permanent (1.84(w)); and sheets must be free of alterations and interlineations (1.84(e)). Uneven hand lettering and lines that fade in reproduction are where hand work usually fails.
Does a provisional application have to meet 1.84?
The rule text sets the standard for drawing sheets in utility applications and does not itself say how it applies to provisionals; that is a question for the USPTO provisional guidance. Because a provisional is often the priority document for a later non-provisional, preparing its sheets to the same measurable rules avoids drawing them twice. Confirm the requirement for your own filing against the current rule and MPEP 608.02; this page is a summary, not advice.
How is the 0.32 cm letter height measured?
On the printed sheet, at final scale — not from the font size in the file. 1.84(p)(3) requires numbers, letters and reference characters to measure at least 0.32 cm (1/8 inch) in height but does not name a metric, so we measure capital letters, the tallest glyphs in most labels. Lower-case letters are shorter than capitals and are not measured separately. Because a drawing is reproduced at two-thirds size, a height that only just passes in the file can fail on the page (1.84(k)).
Can PatentQuill guarantee the USPTO will accept my drawings?
No, and no drafting tool can. PatentQuill checks what can be measured on the sheet: margins, letter height, black-only lines, FIG. labels, sheet numbers, numeral uniqueness and agreement with your text, fit within the sight, and text crossed by lines. It cannot decide whether your figures show every claimed feature, whether the description supports them, or how an examiner will read them. Acceptance is the Office’s decision.
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PatentQuill is a drafting tool, not a law firm, and this page is not legal advice. It summarizes 37 CFR 1.84 for drafting and does not replace the rule text, MPEP 608.02 or advice from your attorney. Confirm every figure against the official sources before you file.