Paper weight demystified

Confused about paper specifications? You’re not alone. Common paper specifications for photo books use the terms “cover stock” (also known as “card stock”) and “text stock” when describing how heavy a paper is.

In the United States the weight of paper stocks are commonly referenced by the weight of 500 sheets of paper. To confuse things the size of the sheet of paper used for determining the spec depends on the type of paper that is being specified. Pound weight for cover paper is the weight of 500 sheets of a 20” by 26” paper. The pound weight of text paper is determined using 500 sheets of 25” by 38” paper. Since the size of paper used for cover and text weight papers is different, 80# cover stock is 1.8 times heavier, or almost twice, than 80# text stock.

Most of our international customers don’t have this confusion since they use a standard term grammage, measured in grams per square meter, or GSM.

Since the density of paper varies by paper type, there is not a direct correlation between weight and thickness. This means that one type of paper that is 200 GSM is not necessarily twice as thick as 100 GSM of another paper type.

At SharedInk we use the heavier, more expensive, cover weight papers as the default papers. Our ordering system automatically switches over to the lighter text weight papers when the book gets too thick for us to bind as the page count goes up. To see how many pages we can get for each type of paper you can read the article in our Knowledge Base.

The following table shows the US printing and metric equivalents for the papers that SharedInk uses.