To find the paper sizes for A, B, and C sheets of the ISO standard, read on!
What is ISO Paper anyway?
ISO (International Organisation for Standardisation) 216 paper sizes are based on an aspect ratio of approximately 1:1.4142 – the square root of 2. The base format (A0) is a sheet spanning 1m² in area. Successive sheets in the series are made by halving the preceding paper size along the larger edge.
The advantage of this system lies in scaling: if a sheet with an aspect ratio of √2 is divided into two equal halves parallel to its shortest sides, then the halves will again have an aspect ratio of √2.
Developed from earlier ideas in Germany in 1922, the system quickly spread to other countries, and was established as an ISO standard in 1975.
A Series
The most frequently used of this series is A4. The US ‘Letter’ paper size – that you may frequently select by mistake in MS Word (as I do) – is 6mm wider and 18mm shorter than this.
Sheet
Dimensions (mm)
A0
1189 x 841
A1
841 x 594
A2
594 x 420
A3
420 x 297
A4
297 x 210
A5
210 x 148
A6
148 x 105
A7
105 x 74
A8
74 x 52
A9
52 x 37
A10
37 x 26
B Series
In less common use, the B Series is the geometric mean of successive A sheets. B sizes are usually found in poster design, books and envelopes.
Sheet
Dimensions (mm)
B0
1414 x 1000
B1
1000 x 707
B2
707 x 500
B3
500 x 353
B4
353 x 250
B5
250 x 176
B6
176 x 125
B7
125 x 88
B8
88 x 62
B9
62 x 44
B10
44 x 31
C Series
The C series is used only for envelopes. The area of C series sheets is the geometric mean of the areas of the A and B series sheets of the same number.
