U.S. Basis Weight, Metric Weight, Points
Paper weight is an important component to consider when printing. Heavier media often conveys quality and provides durability. Unfortunately, sorting through the various methods of labeling a paper’s weight is not always straightforward. First, there are three common methods for specifying paper weight and thickness: U.S. Basis Weight (Bond, Book, Index, Cover, Tag, Points, Offset ), Metric weight (GSM or G/m2) and, often interchangeable, Points or Mils (an actual Caliper reading of the paper thickness).
U.S. Basis Weight
The U.S. Basis (not basic) Weights, are the most confusing, simply because the same paper can yield different values based on the “Basis Weight” applied while manufacturing the paper. And higher values don’t always equate to heavier/thicker print media. For example, a sheet of 100lb Text paper is actually much thinner than an 80lb Cover stock.
The “Basis Weight” is defined as the weight of 500 sheets of paper in its basic unit uncut size, which means before being cut to Letter size or Legal size, the paper is weighed and categorized. The most common sizes, some of which you may recognize, are Bond, Text, Book, Cover, Index and Tag. An uncut sheet of Bond paper is 17 x 22 inches, while an uncut sheet of Cover paper is 20 x 26 inches. If 500 sheets of Bond paper (17 x 22 inches) weigh 20 lbs, then a ream of paper cut to Letter size will be labeled as 20 lb. And if 500 sheets of Cover paper (20 x 26 inches) weigh 65 lbs, then a ream of this paper trimmed to tabloid size would be marked as 65lb. This may be a lot to grasp, but don’t feel overwhelmed! Often professional printers don’t keep track of all the permutations. Based on experience from using a small subset, they have a pretty good idea of what to expect when reaching for a 24lb Bond versus a 60lb Cover versus a 110lb Index.
Paper Weight Conversion Chart
The following table serves as a reference for comparing paper weight across the different scales. The values noted in bold are the most commonly available weights.
For example, let’s say you needed to print 5,000 brochures. A common paper weight for this application might be 100lb Text. Or if you wanted just your basic copy paper for everyday use, you might want to select 24lb Bond.
Understanding paper weights and paper types in the printing industry is not easy. However, it is valuable to have a basic understanding of it, whether you work in retail, advertising, IT, finance, for a small business or in a large corporation.
|US Basis Weights||Caliper||Metric|
|Bond||Text||Cover||Index||1 Point = 0.001″||GSM (g/m2)|