Best Answer: Depends what the ply value is,the number of layers glued together and density of a plywood. *A common rule of thumb is a 4x8 foot sheet of 1/4 fir plywood weighs 25 pounds. There are 32 square feet in a sheet, so a square foot of 1/4 fir plywood weighs about 0.78 pounds. Since 1/2 is twice as thick as 1/4, 1/2 fir plywood weighs twice as much, or 1.56 lbs, and 3/4 three times as much, or about 2.34 lbs. Fir plywood is common, but other species are available. Weight varies considerably between species of wood, so be aware the weight of plywood of different species can be different.