Basis weight is the total weight, in pounds, of a ream of paper. A ream of paper is 500 sheets and is the standard ordering unit for paper. Because paper comes in different sizes and widths, the basis weight of paper can vary from ream to ream. One way to calculate basis weight involves using both metric and customary (inches) units in a formula. To do this you will need a scale, a metric ruler and a normal ruler.
Things You Will Need
Press the zeroing button on the scale and wait until it reads 0. Place one sheet of paper on the scale, then take it off to measure its length and width with the metric ruler. Multiply its length and width to get its area in square meters. For example, if the paper is .2 meters by .7 meters, its area is .14 meters.
Divide the mass of the paper in grams by its area in square meters. Using the example above, if the paper has a mass of 5 grams, you would divide 5 by .14 and get 35.7.
Measure the length and width of the paper in inches, then multiply the two numbers to find its basic area. For example, if the paper was 17 inches by 22 inches, its basic area would be 374 square inches.
Multiply those two products. Using the above numbers, 35.7 x 374= 13,351.8.
Divide this number by 1,406.5. The resulting number is the basis weight of the paper. Using the above numbers, the basis weight of the paper would be 9.49 pounds (13,351.8/1,406.5).