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Standard Specifications
2026-08-14
4 min read
Standard Paper Sizes Guide: A4, A3, B5, Letter in cm & Inches
Comprehensive dimensions table for international ISO 216 paper series (A/B series) and North American ANSI Letter formats in cm, mm, and inches.
1. Overview of ISO 216 International Paper Standards
The ISO 216 standard governs paper sizes used across most countries globally. Designed based on the 1:√2 (approx 1:1.4142) aspect ratio, folding the paper in half maintains the exact same aspect ratio.
2. ISO A-Series Dimensions Reference Table
| Format | Millimeters (mm) | Centimeters (cm) | Inches (in) |
|---|---|---|---|
| A4 (Standard) | 210 × 297 mm | 21.0 × 29.7 cm | 8.3 × 11.7 in |
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