4. Conversion Factors

In order to convert American paper weights into its equivalent weight in grammage, we must first determine the basic ream size.

For example, if an American customer tells us to use 50# pound stock for a job, we must determine whether  it is 50 lbs. cover stock (20” x 26”) or 50 lbs. text stock     (25” x 38”).

For information, a 50 lbs. cover stock weighs  135 gsm while a 50 lbs. text paper weighs only 74 gsm although in pounds , both appear similar.

Table #7 gives some conversion factors used to multiply with the given pound weight to get the equivalent weight in grams per square metre. Note that the basic ream size dimensions must first be established.

Table # 7

 Another method to work out the equivalent weight in gsm is to use the following formula