# item.guide
Side-by-Side Comparison North American (ANSI & Arch)

ANSI D vs. US Letter

Comparing 2 standards across 10 specifications. 10 key differences identified.

Comparing:
ANSI D
US Letter

ANSI D is an engineering drawing paper standard defined by ANSI/ASME Y14.1, measuring 22.0 × 34.0 inches (558.8 × 863.6 mm). Formed by doubling ANSI C, it is the classic North American engineering blueprint format for civil engineering site plans, automotive chassis designs, and aerospace sub-assemblies.

View full ANSI D spec sheet →

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.

View full US Letter spec sheet →

Specification Comparison Table

10 Parameters
Parameter / Spec
Width × Height (Imperial)
22.00 × 34.00 in 8.50 × 11.00 in
Width × Height (Metric)
558.8 × 863.6 mm 215.9 × 279.4 mm
Aspect Ratio
1 : 1.5455 (11 : 17 — identical to ANSI B) 1 : 1.2941 (17 : 22 — not √2)
ANSI Hierarchy
ANSI D = 2 × ANSI C = 4 × ANSI B = 8 × ANSI A
International ISO Equivalent
A1 (594 × 841 mm)
Primary Applications
Civil engineering utility plans, automotive chassis CAD plots, aerospace mechanical 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)