Arch D

Direct Answer

Arch D (Architectural D) is the dominant commercial architectural drawing paper format in the United States, measuring exactly 24.0 × 36.0 inches (609.6 × 914.4 mm). Operating on a clean 2:3 aspect ratio, it is the mandated standard for US building permit architectural blueprints, construction site floor plans, and residential elevations.

Source: AIA (American Institute of Architects) / U.S. National CAD Standard · Last reviewed Aug 28, 2026

Specs

Width × Height (Imperial)	24.00 × 36.00 in
Width × Height (Metric)	609.6 × 914.4 mm
Aspect Ratio	2 : 3 (1 : 1.5000 — whole integer aspect ratio)
Arch Series Hierarchy	Arch D = 2 × Arch C (18×24 in) = 4 × Arch B (12×18 in) = 8 × Arch A (9×12 in)
Comparison to Engineering ANSI D	Arch D (24×36 in) is 2 inches wider and 2 inches longer than ANSI D (22×34 in)
Plotter Roll Standard	Standard 24-inch and 36-inch wide wide-format bond rolls
Primary Applications	US building permit sets, architectural floor plans, structural framing blueprints, MEP schematics

The 24×36-Inch Construction Standard

In US building construction, 24 × 36 inches (Arch D) is the most commonly used blueprint sheet format. Commercial building plan review departments, general contractors, and job-site trailer plan tables are typically sized around 24×36 sheets. Its clean 2:3 (4:6) integer aspect ratio matches standard architectural drafting scales (1/4" = 1'0").

Architectural Arch Series vs Engineering ANSI Series

Architects in North America use the Arch series (Arch A 9×12, Arch B 12×18, Arch C 18×24, Arch D 24×36, Arch E 36×48), while mechanical engineers use the ANSI series (ANSI A 8.5×11, ANSI B 11×17, ANSI C 17×22, ANSI D 22×34, ANSI E 34×44). Mixing these causes clipping on standard roll plotters.