Popular A series Paper Sizes

 

𝐀4 𝐬𝐢𝐳𝐞 𝐢𝐬 𝐝𝐞𝐟𝐢𝐧𝐞𝐝 𝐚𝐬 210 𝐦𝐦 𝐱 297 𝐦𝐦 𝐚𝐧𝐝 𝐧𝐨𝐭 𝐥𝐢𝐤𝐞 𝐬𝐨𝐦𝐞𝐭𝐡𝐢𝐧𝐠 𝐚𝐬 200 𝐦𝐦 𝐱 300 𝐦𝐦. This specific size is derived from a calculation mentioned in this article. Paper size standards govern the size of sheets of paper used for writing paper, stationery, cards, and for some printed documents.

The ISO 216 standard, which includes the commonly used A4 size, is the international standard for paper size. It is used across the world except in North America and parts of Central and South America, where North American paper sizes such as "Letter" and "Legal" are used. The international standard for envelopes is the C series of ISO 269.

A Series:
𝐓𝐡𝐞𝐫𝐞 𝐚𝐫𝐞 11 𝐬𝐢𝐳𝐞𝐬 𝐢𝐧 𝐭𝐡𝐞 𝐀 𝐬𝐞𝐫𝐢𝐞𝐬, 𝐝𝐞𝐬𝐢𝐠𝐧𝐚𝐭𝐞𝐝 𝐀0–𝐀10, 𝐚𝐥𝐥 𝐨𝐟 𝐰𝐡𝐢𝐜𝐡 𝐡𝐚𝐯𝐞 𝐚𝐧 𝐚𝐬𝐩𝐞𝐜𝐭 𝐫𝐚𝐭𝐢𝐨 𝐨𝐟 𝐬𝐪𝐫𝐭 𝐨𝐟 2.
a/b = sqrt (2) = 1.414 (Approximately) where a is the long side and b is the short side.

The A0 base size is defined as having an area of 1 m2
a= 1189 mm, b=841 mm, a/b = 1.414
Area of A0 = 1189 mm x 841 mm = 1 m2

Since A-series sizes share the same aspect ratio (√2), they can be scaled to other A-series sizes without being distorted, and two sheets can be reduced to fit on exactly one sheet without any cut-off or margins.

Paper sizes and approximate area in m2

✱ A0 = 841 x 1189 mm = 1.000 m2
✱ A1 = 594 x 841 mm = 0.500 m2
✱ A2 = 420 x 594 mm = 0.249 m2
✱ A3 = 297 x 420 mm = 0.125 m2
✱ A4 = 210 x 297 mm = 0.062 m2
✱ A5 = 148 x 210 mm = 0.031 m2
✱ A6 =  105 x 148 mm = 0.016 m2
✱ A7 = 74 x 105 mm = 0.008 m2
✱ A8 = 52 x 74 mm = 0.004 m2
✱ A9 = 37 x 52 mm = 0.002 m2
✱ A10 = 26 x 37 mm = 0.001 m2