When 30 Equals 33: America's Bizarre Methods of Calculating the Weight of Paper

There’s never been a better time for U.S. buyers of graphic paper to understand what GSM (grams per meter) means, and how messed up our own system of basis weights is.

A page of 30# newsprint, you see, weighs the same as a 33# page of magazine-quality paper (and of other publication grades that use the "book, text, offset" method of calculating basis weight). But two same-sized sheets of 48.9 gsm always weigh the same, regardless of whether one is copy paper and the other wallpaper or tissue or newsprint….