A Series

Paper in the A series format has an aspect ratio of 1:√2 ≈ 0.707 (rounded to the nearest millimetre). The A series of paper is the most commonly used worldwide, with only the US and Canada not currently conforming to the ISO standard. Mexico, Venezuela, Colombia, Chile and the Philippines also favour the US letter format, despite having officially changed to the ISO standard. The most frequently used paper size in this series is A4, which measures 210 x 297mm – that’s 6mm narrower and 18mm longer than the US Letter paper size; the equivalent of A4 in the North American system.

ISO A-Series Paper Size Table

Download A Series Paper Sizes PDF Factsheet

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A Series Paper Sizes
A4 Paper Size
US Letter Paper Size
Billboard Sizes
Newspaper Sizes
ISO Envelope Sizes
US Envelope Sizes
ANSI Paper Sizes
Business Card Sizes
Photo Sizes
Old Imperial Sizes
Canadian Paper Sizes
North American Architectural Sizes


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