Homewyse Calculator: Cost to Install Asphalt Shingle Roof- calculate asphalt ,The cost to Install a Asphalt Shingle Roof starts at $3.26 - $4.29 per square foot, but can vary significantly with site conditions and options. Get fair costs for ...How to Calculate Asphalt Prices | SciencingMeasure the asphalt pavement area. Take all measurements and calculate the area by multiplying the length by the width in feet for square or rectangular areas.