Paper Sizes and Dimensions: Your Complete Guide

The ISO 216 defines the paper measurements of the “A”, “B” and “C” series of paper sizes. The most commonly used series of paper sizes is the A-series, with the international letterhead size A4 being the most widely used within that series.

There are many common questions surrounding the A-series of paper sizes. What is bigger, A3, A4 or A5? Is A3 bigger than A5? What are the standard paper sizes? What size is A4 in cm?

We’re here to answer those questions and to clue you in on everything you need to know about international paper sizes and dimensions.

A paper size chart

Standard A Paper Sizes

Paper Size	Inches (in)	Centimetres (cm)	Millimetres (mm)
A0	33.1 x 46.8 in	84.1 x 118.9 cm	841 x 1189 mm
A1	23.4 x 33.1 in	59.4 x 84.1 cm	594 x 841 mm
A2	16.5 x 23.4 in	42 x 59.4 cm	420 x 594 mm
A3	11.7 x 16.5 in	29.7 x 42 cm	297 x 420 mm
A4	8.3 x 11.7 in	21 x 29.7 cm	210 x 297 mm
A5	5.8 x 8.3 in	14.8 x 21 cm	148 x 210 mm
A6	4.1 x 5.8 in	10.5 x 14.8 cm	105 x 148 mm
A7	2.9 x 4.1 in	7.4 x 10.5 cm	74 x 105 mm
A8	2 x 2.9 in	5.2 x 7.4 cm	52 x 74 mm

What Does GSM Paper Mean?

While looking for the perfect paper size, you may have noticed a GSM number (grams per square metre, also known as g/m²). GSM is a measurement of the thickness or density of the paper.

This measurement is calculated by weighing the piece of paper, in grams, if it were exactly one square metre in size.

Paper measured with a higher GSM will generally be thicker and more durable. Thus making it more difficult to crease and tear.