Bulk is a measurement of paper that often determines what type of printers can handle it. Bulk is used to measure the ratio of paper thickness to its weight in cubic centimeters per gram. The formula for bulk is thickness (mm) x basis weight (g/m^2) x 1000. Basis weight is another property of paper you must know to determine bulk. Basis weight is also known as "grammage" and measures the weight of paper per unit area, expressed in grams per square meter.
Determine the thickness of the paper for which you want to calculate the bulk. Thickness, also known as caliper, is measured with a micrometer. See Resources to find the thickness for different paper types, measured in mm.
Determine the basis weight of the paper, measured in g/m^2. See Resources to find the grammage, or basis weight in g/m^2 of various paper types.
Multiply the two values from steps 1 and 2 together.
Multiply the result in step 3 by 1,000 to get the paper bulk in cm^3/g.
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