The formula to calculate the weight of asphalt material in a given area is equal to the volume of the material multiplied by the density of the material. Generally, the volume is measured in cubic feet, and is calculated by multiplying the surface area by the thickness of the asphalt.
The density of hot asphalt mix varies by the mix proportion and the type of aggregate material used; it is generally measured in terms of pounds per cubic foot. Thus, the initial weight of the material is given in pounds. As there are 2,000 pounds per ton, dividing the weight by 2,000 yields the tonnage of asphalt.