Choosing the Correct Paper Weight

Read all about paper weights here. This article will help you choose the correct paper weight for your needs.

Paper Weights


What people mean when they talk about the weight of a sheet of paper or card is effectively the thickness of that piece of paper. There are two conventions currently in widespread use for paper weights.


The first, as specified by ISO 536, is used in Europe and most parts of the world that use ISO paper sizes, apart from the few countries that still use US paper sizes, is grams per square meter (g/m2 or commonly gsm). This commonly called grammage in non English speaking countries, a term we will use on this site to differentiate it from the North American basis weights.


The second is used in those countries that use US paper sizes such as the United States and Canada. This is known as the basis weight and is usually specified in pounds (lbs). The basis weight is the weight of a 500 sheet ream of uncut paper.


Paper Weight


The weight of a sheet of paper depends on the size of the sheet and the thickness of the paper, known as grammage internationally and basis weight in North America. The tables below give the weights of sheets of the ISO 216 A paper sizes for various common grammages (e.g. 80gsm, 90gsm, 120gsm) in grams in the first table and in ounces in the second table.


The ISO A series paper sizes are 4A0, 2A0, A0, A1, A2, A3, A4, A5, A6, A7, A8, A9 and A10, see  Paper Sizes for more information about a series and US Paper Sizes.

Weight in Grams


The weight of paper in countries that use ISO paper sizes is defined by ISO 536 Paper and Board - Determination of Grammage. This standard defines grammage as grams per square meter (g/m2) thus the weight of a single sheet of A0 paper defines the grammage of that paper type as the A0 size is defined by ISO 216 as having an area of 1 square meter. An A0 sheet of 80gsm paper will weigh 80 grams, an A0 sheet of 100gsm paper will weigh 100 grams and so on.


Note gsm is commonly used rather than g/m2 in most day to day use. This came about because of the inability of early computer packages to display super-scripted characters - especially stock control, accounting and invoicing systems.


Paper that is used in offices is usually between 70gsm and 80gsm, with 80gsm being the most commonly found weight. Some accountants and solicitors use heavier weight paper ranging from 90gsm to 120gsm for formal correspondence. Above 120gsm come various thicknesses of card with 160gsm and 200gsm being most commonly used for file dividers. Newspaper ranges between 45gsm and 50gsm.

Basis Weight


Basis weight is a much older convention for defining the weight of paper and was widely used in the UK and Europe as well as in North America, where it is still used, up until the international standardization of paper sizes by ISO 216 and its national predecessors in European countries.


Basis weight is defined as the weight of a ream of the uncut paper in pounds (lb) (Note: the # is often used in place of lb when referring to basis weights). The uncut paper sizes being the size used in the manufacturing process before the paper was cut to size. There are many different types of uncut paper, those in common use for the production of office paper and card are Bond Stock, Cover Stock and Index Stock. The word Stock is often dropped when referring to the different types of paper in their finished cut sizes.


Thus if you have a sheet of 20lb Bond Letter paper it will be the exactly the same thickness as 20lb Bond Legal, although the two sheets will weigh different amounts because of the difference in size. However a sheet of 28lb Bond Letter size paper would not be the same as a sheet of 28lb Cover Letter size paper as the uncut sizes for Bond and Cover are different.


Paper that is used in offices is most commonly 20lb or 24lb Bond. Often suppliers will omit the words Bond and just give the basis weight as 20lb or 24lb, although Index and Cover are almost invariably used as this differentiates the other types from the 'default' Bond. 60lb and 65lb Cover and 90lb and 110lb Index are types of light to medium card often used as file dividers, with 80lb, 90lb and 100lb Cover being heavier weight card.


Newspaper has its own stock type, Newsprint, that measures 24" x 36" in uncut size. This is much larger than the Bond and Cover uncut sizes, thus the most common 30lb Newsprint is actually a much thinner paper than 20lb bond. The following page covers the different stock types generally available.



Weight Chart


Weights Of Sheets Of A Series Paper Sizes In Grams
Size 75gsm 80gsm 90gsm 100gsm 110gsm 120gsm 160gsm
4A0 300g 320g 360g 400g 440g 480g 640g
2A0 150g 160g 180g 200g 220g 240g 320g
A0 75g 80g 90g 100g 110g 120g 160g
A1 37.5g 40g 45g 50g 55g 60g 80g
A2 18.75g 20g 22.5g 25g 27.5g 30g 40g
A3 9.38g 10g 11.25g 12.5g 13.75g 15g 20g
A4 4.69g 5g 5.63g 6.25g 6.88g 7.5g 10g
A5 2.34g 2.5g 2.81g 3.13g 3.44g 3.75g 5g
A6 1.17g 1.25g 1.41g 1.56g 1.72g 1.88g 2.5g
A7 0.59g 0.63g 0.70g 0.78g 0.86g 0.94g 1.25g
A8 0.29g 0.31g 0.35g 0.39g 0.43g 0.47g 0.63g
A9 0.15g 0.16g 0.18g 0.20g 0.21g 0.23g 0.31g
A10 0.07g 0.08g 0.09g 0.10g 0.11g 0.12g 0.16g