It can be very difficult and confusing to understand the terminology behind paper weights. We have put together this guide to help understand and clear up the measurements.
There are two basic systems in use; the U.S. system which denotes the weight in pounds (#) or the Metric system which indicates the weight in grams / meter square (g/m2).
The U.S. system is more difficult to understand because the same number in #'s can be used for thicker card stock or thinner text papers. Whereas the metric system is standard across all weights of papers.
For example, a card stock may be a 80# Cover or 80# Text. But in the Metric system, the same papers would simply be 216 g/m2 and 104 g/m2, respectively (the first being twice as thick as the second)
Therefore, we have provided the following chart to help see how the #'s translate to g/m2. We have also tried to provide reference points with things you can find in your house.
For example, regular copy paper and a standard 3 x 5 Index Card.
Arranged from Lightest to Heaviest Papers