Measure Mweight (the weight of 1,000 sheets of paper) by providing the sheet size, basis weight, and basic size of the paper. When filling in these fields, use decimal fractions where necessary and give lengths in inches and weight in pounds.
MWeight Calculator 

The numerical results from this calculator are estimates only and are not guaranteed. Individual mills may use slightly different methods of calculating Mweight. Also, certain products—particularly highercaliper SBS and recycled board—can vary dramatically in basis weight (and therefore Mweight). Lastly, actual selling Mweight may be calculated on the full width of the roll (i.e., size plus waste), thereby increasing the Mweight amount. Please call your sales representative to confirm Mweight.
Example
Find the Mweight for a sheet of 11″ × 17″ book paper with a basis weight of 70 lbs.
Formula:
(Area of Given Sheet) × Basis Weight Area of Basic Size 
=  Rounded Ream Weight × 2  =  Mweight 
Equation:
(11 × 17) × 70 (25 × 38) 
=  13.78 × 2  =  27.56 
Note that in this example, the area of the given sheet size is 11 × 17 = 187 inches^{2} (i.e., less than 336 inches^{2),} according to the Mweight rounding rules below, ream weight should be rounded to the nearest hundredth of a pound.
Specifications
MWeight Rounding Rules  

Sheet Size  Ream Weights 
864 inches^{2} >  Ream weight calculated to nearest pound, e.g.: 148 lbs. 
336 – 864 inches^{2}  Ream weight calculated to nearest half pound, e.g.: 148.5 lbs. 
< 336 inches^{2}  Ream weight calculated to nearest one hundredth of a pound, e.g.: 148.57 lbs. 
Terms & Definitions
Ream: 500 sheets of paper cut to a given standard size for a particular grade.
Ream Weight: The weight of 500 sheets of paper.
Mweight: The weight of 1,000 sheets of paper (or two reams).
Basis Weight: The weight of a ream, measured in pounds. (See supplemental tables below.)
Basic Size: The standard sheet size from which the basis weight of a given grade of paper is determined.
Supplemental Tables of Approximate Basis Weights

