How to Find the Ream Weight of a Paper Type

If you know the actual size of the sheets of paper you are weighing, its basis weight, and its basic size, then you can calculate the ream weight without putting the ream of paper on a scale. 

What Is Basis Weight?

The weight, measured in pounds, of 500 sheets of paper in that paper's basic sheet size is its basis weight. Even after the paper is trimmed to a smaller size, it is still categorized by the weight of its basic size sheet. The basis weight is indicated on the packaging of most papers. However, the basic sheet size is not the same for all. 

What Is Basic Size?

Different types of papers are assigned different basic sheet sizes:

• Bond, copy paper, ledger paper, and rag paper all have a basic sheet size of 17 inches by 22 inches.
• Offset, book, text, and coated papers have a basic sheet size of 25 inches by 38 inches.
• Cover stock has a basic sheet size of 20 inches by 26 inches.
• Tag stock has a basic sheet size of 24 inches by 36 inches.
• Index stock has a basic sheet size of 25.5 inches by 30.5 inches.
• Bristol stock has a basic sheet size of 22.5 inches by 28.5 inches.

Calculating Ream Weight

To calculate the ream weight, multiply the actual sheet size by the paper's basis weight and divide the result by the paper's basic size.

Using this formula, the ream weight of 500 sheets (one ream) of tabloid size 11-inch-by-17-inch, 24 lb. book paper with the basic size of 25-inches-by-38-inches is:

(11x17) x 24 / 25x38 = ~ 4.72 pounds