Patent Drawing Requirements

When drawings are required

Most offices require drawings whenever they are necessary to understand the invention, which covers nearly every mechanical, electrical, or device invention and many processes, often shown as flowcharts.

Common formal rules

The United States sets drawing standards in 37 CFR 1.84, and international applications follow PCT Rule 11. Details vary by office, but the principles are similar.

• Black, durable line drawings; color and photographs only in limited cases
• Standard sheet size (A4 or U.S. letter) with minimum margins
• Figures numbered consecutively (Fig. 1, Fig. 2…)
• Reference numerals that also appear in the description
• Legible lettering and no unnecessary text on the drawing

Consistency with the text

Every reference numeral in a figure should be explained in the description, and every feature in the claims should be visible in at least one figure when drawings are needed. Inconsistencies trigger objections and can be hard to fix without adding new matter.