20 pounds
The weight of copy paper is stated as 20-lb bond, 24-lb bond, etc. This is the weight of 500 sheets (one ream) of basic size sheets. For bond paper, a basic size sheet is 17x22 inches. Thus, that 500 sheets of basic size equals four reams of 8.5x11 copy paper. One ream is then 5 lbs. Verified by picking one up and taking it over to a shipping scale. Next to Vellum 17 is Vellum 27, which weighs .054 pounds or 24.493 grams per piece. The weight of a piece of Vellum 29 is .058 pounds or 26.308 grams while Vellum 30 weighs 0.06 pounds or 27.215 grams per piece. Solid Text 60 as well as Parchment Text 60 weigh .12 pounds or 54.431 grams. As an example, a ream of 20 pounds paper with the size of 8.5 by 11 inches has a weight of five pounds. Below are the weights of the different types of the material that are commonly used for writing as well as for printing. The way we talk about paper in the United States is amazingly convoluted. The short answer is that 500 sheets of bond paper with a size of 17 by 22 have a weight of 20 pounds. The manufacturer would cut a sheet that big into four letter-size sheets, so a 500-sheet ream of 20-pound bond paper weighs 5 pounds. If it was something other than bond paper, then the size of the standard sheet used to determine the weight might be different.  This measures 297mm x 210 mm. It comes in packs of 500 sheets. So, a pack would 'measure' 0.297 x 0.210 x 500 sq metres = 31.185sq m. At 80 grams per sq m this equates to a total weight of 2494.8 grams ~ almost 2.5 kilos.  A piece of printing paper usually weighs 60 grams to 120 grams. The normal weight of this material does not exceed 160 grams. When the weight of the material exceeds 160 grams, it is considered as a card. As an example, a ream of 20 pounds paper with the size of 8.5 by 11 inches has a weight of five pounds. Below are the weights of the different types of the material that are commonly used for writing as well as for printing. An uncut sheet of Bond paper is 17 x 22 inches, while an uncut sheet of Cover paper is 20 x 26 inches. If 500 sheets of Bond paper (17 x 22 inches) weigh 20 lbs, then a ream of paper cut to Letter size will be labeled as 20 lb. And if 500 sheets of Cover paper (20 x 26 inches) weigh 65 lbs, then a ream of this paper trimmed to tabloid size would be marked as 65lb. This may be a lot to grasp, but don’t feel overwhelmed! The short answer is that 500 sheets of bond paper with a size of 17 by 22 have a weight of 20 pounds. The manufacturer would cut a sheet that big into four letter-size sheets, so a 500-sheet ream of 20-pound bond paper weighs 5 pounds. 100 sheets weigh 1 pound. 1 Sheet weighs .16 ounces. 6.25 sheets per ounce. Not an expert here, but I think 20 lbs refers to 2000 sheets, not 500. The weight of a single sheet at 500 sheets per, would be 0.64 oz. - way too much for a sheet of paper, by about a factor of 4.
https://answers.yahoo.com/question/index?qid=20071012094206AAKCcuY http://www.tellmehowmuch.net/how-much-does-a-piece-of-paper-weigh.html http://home.howstuffworks.com/question329.htm http://www.answers.com/Q/How_many_pounds_do_500_pieces_of_paper_weigh http://www.tellmehowmuch.net/how-much-does-a-piece-of-paper-weigh.html http://www.okidata.com/understanding-paper-weight https://answers.yahoo.com/question/index?qid=20060923202022AAJNUV1
how much does a pack of printing paper weigh