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March 16th, 2015

Paper Weight Conversion Chart

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by David Rogers

There’s no beating around the bush: The different measurements of paper weight can get confusing very quickly.

This stems from the way different types of paper are measured, as well as different measurement types being used for different applications. We’ve put together a paper weight conversion chart to represent popular paper weights used in book printing, as well as a few common reference points.

Paper Weight Conversion Chart

As an explanation for the reference points, standard copy paper you’re familiar with is normally 20 lb. bond paper, the equivalent of 50 lb. offset text paper. The glossy paper used for many magazines is typically 80 lb. gloss text paper. Some paper types are more commonly measured in points, such as 10 pt. C1S, which is our most common paperback book cover stock. Also note that the measurement of Point refers to thousandths of an inch. You can find more from our blog on book cover stock options for paperback books.

Just because a paper is thicker does not necessarily mean it is better for all uses. For instance, since a novel page is typically around 60 lb. text paper, using a page much thicker than that will result in a book that is very stiff and difficult to hold open.

While the sizes and paper weights listed in the chart are the most common types and weights used by book printers, this is not an exhaustive list of all paper types.

The Basis Weight of Paper

In the U.S., the traditional method of determining paper weight is formally known as basis weight, and is the weight (in pounds) of a stack of 500 sheets of paper. This is where much of the confusion comes in, because different types of paper have different uncut sizes used as the basis of this weight.

As an example, the paper weight of bond paper is determined by the weight of a stack of 500 “basis size” bond sheets – which are 17” x 22”. On the other hand, the “basis size” of uncut text paper is 25” x 38”.

Here’s a Basis Weight Chart of some of the major paper types.

Basis weight size chart by type of paper

Paper Thickness versus Paper Weight

It is important to note that paper thickness and paper weight are not the same thing. The type of paper affects how thick that sheet will be for any given basis weight. For instance, a sheet of 100 lb. offset cover is about 14 pt., or 0.0140 inches thick. However, 100 lb. gloss cover, which has the same basis weight, is closer to 9 pt. (o.0092 inches). As a result, the 14 pt. offset cover stock is quite a bit stiffer than the equivalent gloss cover stock.

Hopefully these charts will be helpful to you as you determine the paper you want to use for your book. You can choose the types of paper for both the cover and the inside pages of your book as you use our quote form. But as always, feel free to give us a call at 888-664-8166 for a recommendation or if you have questions about your specific project – we’ll be glad to help!