A0 vs. A4
Comparing 2 standards across 9 specifications. 9 key differences identified.
A0 is the base unit of the ISO 216 international paper standard, defined with an exact surface area of 1 square meter (1.000 m²) and dimensions of 841 × 1189 mm (33.1 × 46.8 inches). Operating on the 1:√2 Lichtenberg aspect ratio, it is the global standard for large architectural CAD plots, engineering schematics, and academic conference poster presentations.
A4 is the international standard paper format defined by ISO 216, measuring 210 × 297 mm (8.27 × 11.69 inches). Utilized by over 140 countries representing approximately 95% of the world's population, it is the universal standard for business letters, official contracts, academic papers, magazine publishing, and desktop office printers.
Specification Comparison Table
9 Parameters| Parameter / Spec | ||
|---|---|---|
|
Width × Height (Metric)
|
841 × 1189 mm | 210 × 297 mm |
|
Width × Height (Imperial)
|
33.1 × 46.8 in | 8.27 × 11.69 in |
|
Nominal Surface Area
|
1.000 m² (1,000,000 mm²) | 0.0625 m² (1/16 m² — 62,500 mm²) |
|
Exact Aspect Ratio
|
1 : √2 (1 : 1.4142 — Lichtenberg ratio) | 1 : √2 (1 : 1.4142) |
|
Weight of Standard 80 gsm Sheet
|
80.0 grams exactly | 5.0 grams exactly |
|
Halving Relationship
|
Cut in half across length yields 2 sheets of A1 | — |
|
Primary Applications
|
Architectural blueprints, GIS cartography, technical CAD schematics, academic research posters | — |
|
Weight of 500-Sheet Ream (80 gsm)
|
— | 2.50 kg (5.51 lbs) |
|
Postal Envelope Pairings
|
— | C4 (unfolded), C5 (folded once), C6 (folded twice), DL (folded in thirds) |