How Much Asphalt Do I Need?
Asphalt is sold by the ton. One ton covers about 80 square feet at a compacted 3-inch depth.
Worked example
A 40 ft × 12 ft driveway at 3 inches = 480 × (3 ÷ 12) = 120 cubic feet. At ~145 lb/cu ft that is roughly 8.7 tons.