Side-by-Side Comparison
North American (ANSI & Arch)
Arch D vs. US Letter
Comparing 2 standards across 11 specifications. 11 key differences identified.
Comparing:
Arch D
US Letter
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.
US Letter (ANSI A) is the standard business and consumer paper size in the United States, Canada, and parts of Mexico, measuring exactly 8.5 × 11.0 inches (215.9 × 279.4 mm). Standardized under ANSI/ASME Y14.1, it is slightly wider and shorter than the international ISO 216 A4 format.
Specification Comparison Table
11 Parameters| Parameter / Spec | ||
|---|---|---|
|
Width × Height (Imperial)
|
24.00 × 36.00 in | 8.50 × 11.00 in |
|
Width × Height (Metric)
|
609.6 × 914.4 mm | 215.9 × 279.4 mm |
|
Aspect Ratio
|
2 : 3 (1 : 1.5000 — whole integer aspect ratio) | 1 : 1.2941 (17 : 22 — not √2) |
|
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 | — |
|
ANSI Series Designation
|
— | ANSI A (Base engineering format) |
|
Comparison to ISO A4
|
— | US Letter is 5.9 mm wider and 17.6 mm shorter than A4 (210 × 297 mm) |
|
Standard Office Weight
|
— | 20 lb Bond (approx. 75 gsm) or 24 lb Bond (approx. 90 gsm) |
|
Matching Envelope Standard
|
— | US #10 Envelope (4.125 × 9.50 in / 104.8 × 241.3 mm) |