So if they are both 80 lb. why does the 80 text look and feel much thinner than the 80 cover stock? The secret is that paper weights are measured in standard sheet sizes. (Called “basis sheet sizes” in the trade.) But the standard sizes are different for different types of paper.
The text paper is measured using a standard size of 23 x 35 inches. The cover stock is measured using a standard size of 20 x 26 inches. It is a heavier stock but a much smaller size sheet.
So, 1,000 sheets of text (at 23 x 35 inches) weigh 80 lbs. And 1,000 sheets of cover stock (at 20 x 26 inches) also weigh 80 lbs. Ha!
Another good question is why does a 50 lb. offset text stock feel the same as a sheet of 20 lb. bond or standard copy paper? Can anyone guess? Because of the basis sizes! The offset is based on 23 x 35” and the bond, 17 x 22”. Although its confusing, there is a reason. So now you know the paper mystery!