Knowing a paper’s weight is important when working on paper engineering and pop-up designs because the thickness of the paper is the feature that most defines its stiffness. Finding the weight of a piece of paper can be tricky if you don’t have the original packaging. Use the following table to convert different paper weights and thicknesses:

Microns Thousandths of an Inch Grams/Meter2 Pounds (Bond Paper)
80 3.1 60 16
120 4.7 90 24
150 5.9 115 31
180 7.1 150 40
200 7.9 180 47
230 9.1 220 58
250 9.8 250 67
330 13.0 285 76
380 15.0 315 87
445 17.5 385 105