35 U.S.C. · Part II · Chapter 11, Application for patent
35 U.S.C. 113: Drawings
In plain English
Section 113 requires a drawing wherever one is needed to understand the subject matter to be patented. In practice nearly every application for a machine, article, circuit or system has drawings, and most method applications include at least a flowchart. Purely chemical inventions defined by formula are the main exception.
If the invention can be illustrated and the applicant has filed no drawing, the USPTO may require one, giving at least two months to supply it. But drawings filed after the filing date cannot be used to cure an inadequate disclosure or to support the interpretation of a claim. Anything a later drawing shows that the original text and drawings did not is new matter.
Section 113 says what must be shown; the format rules are in 37 CFR 1.84, which covers black and white line drawings, sheet size, margins, views, reference numbers and the limited cases where color drawings or photographs are accepted.
Annotation by Raj Sutariya, Co-founder, PatentAssist.ai. General information, not legal advice; the statute below governs.
Text of 35 U.S.C. 113
Current text, quoted from the official United States Code.
The applicant shall furnish a drawing where necessary for the understanding of the subject matter sought to be patented. When the nature of such subject matter admits of illustration by a drawing and the applicant has not furnished such a drawing, the Director may require its submission within a time period of not less than two months from the sending of a notice thereof. Drawings submitted after the filing date of the application may not be used (i) to overcome any insufficiency of the specification due to lack of an enabling disclosure or otherwise inadequate disclosure therein, or (ii) to supplement the original disclosure thereof for the purpose of interpretation of the scope of any claim.
Practical notes
Rule 1.83(a) requires the drawings to show every feature specified in the claims. A claim element that appears in no figure invites an objection and, worse, makes it harder to argue that the element was described. Check every claim term against the figures before filing.
Treat drawings as part of the disclosure, not an afterthought. Under section 113 you cannot add them later to support claims, and a provisional application without the figures you later rely on may not support the priority claim. Our patent drawing requirements guide compares the USPTO rules with the EPO's and India's.
Informal drawings are enough for a filing date. If the USPTO objects to their form, corrected sheets can be filed later as long as they add no new matter.
Related rules and guidance
- 37 CFR
- § 1.81, § 1.83, § 1.84, § 1.152
- MPEP
- 601, 608
Read next
All annotated sections of 35 U.S.C.
Statute text from the United States Code published by the Office of the Law Revision Counsel of the U.S. House of Representatives (uscode.house.gov). Text contains those laws in effect through Public Law 119-124 (October 15, 2026). Editorial notes and footnotes are omitted. The annotations are general information, not legal advice; check the official text and a registered patent practitioner before relying on them.