In Europe, paper grammage is measured in grams per square meter. One A4 size (210 x 297 mm) sheet of paper is, by definition, 1/16th of a full square meter. Printer or photocopier paper is typically 80 g/m², implying that each A4 sheet weighs 5 grams.
In the United States of America, the corresponding basis weight, is measured in pounds per ream, where each ream is 500 sheets, each 24 x 36 inches.
1 pound/ream = 1.63 g/m²
The three common grammages for newsprint in North America are 45.6, 48.8 and 52.1 grams, which correspond to basis weights of 28, 30 and 32 pounds.
See also Quality
Measures: Newsprint by Ruth Felland.