What Paper Weight is it?--Understanding Paper Weights
Written by Jaime Zuniga
The American measures of paper weights are nothing if not confusing. The weight (e.g. 80 pounds, or 80#) of a paper refers to the weight of 500 sheets in the paper's basis size (there are 500 sheets in a ream). The basis size varies with the type (grade) of paper. Here are some of the most common types of paper and their basis size (also called basic size or parent size); measured in inches:
Bond & Writing -- 17 x 22
Offset & Coated Book -- 25 x 38
Bristol -- 22-1/2 x 28-1/2
Index -- 25-1/2 x 30-1/2
Cover -- 20 x 26
The weight and grade of paper you probably use in your copier is 20# bond. Bond paper comes in a basis size of 17 x 22 (although you buy it already trimmed to a smaller size). But 500 sheets of 17 x 22 copier paper would weigh 20 pounds -- hence 20# bond.
The same thickness of paper in an offset grade is called 50# offset, because the basis size of offset paper is larger -- 25 x 38 -- and 500 sheets of it weighs 50 pounds. So now you understand why 20# bond is the same thickness as 50# offset, and why 24# bond is the same as 60# offset, etc.
Common weights of the various grades we use at Miller Sherwood Printing Company:
Bond -- 20#, 24#, 28#, 32# (copier & digital paper)
Offset -- 60#, 70# (heavier paper)
Coated Book -- 80#, 100# (heavier paper)
Writing -- 20#, 24# (stationery papers)
Bristol -- 67# (inexpensive card stock)
Index -- 90#, 110# (smooth card stock)
Cover -- 80#, 100# (various card stocks)
And to top it all off some cover stocks are named for their thickness, for example, 10 point (10pt) cover stock calibrates to 0.010 of an inch in thickness. These stocks are named board stocks and are available in uncoated, coated one and two sides, in gloss or high gloss finishes. Usually available in white, there are other colors available.
Board stocks used at Miller Sherwood Printing Company are coated 1 and 2 sides, gloss and high gloss:
8pt, 10pt, 12pt. 14pt, 16pt