Asphalt, when compacted weights approximately 118 lbs. Per square yard 1 inch thick. So for example if you have 10sy, that is 4" thick, it would weight approximately 4,720lbs. Or 2.36 tons. You take 118 x 4, which equals 472lbs. Then you multiply this by the square yards (10 x 472) then you divide this product by 2,000 (1 ton is 2,000lbs. And asphalt is sold by the ton) This is a good tool for estimating however, to get the exact weight of asphalt you first need to know the specific gravity of the asphalt being produced that day, (this number changes on a day-to-day basis.) then you multiply that number by the weight of one cubic foot of water, which is 62.416lbs. However, just using this simple formula should work out very well for estimating the weight of asphalt.