Asphalt Calculator

Asphalt formula

Cubic feet = Length (ft) x Width (ft) x Thickness (in) / 12
Order volume = Cubic feet x (1 + waste %)
Tons = Order volume x 145 lb / 2,000  (about 1.96 tons per cubic yard)
Cost = Tons x price per ton

Worked example

A new 60 x 20 ft driveway paved 4 in thick with 5% waste: 60 x 20 x (4 / 12) = 400 cubic feet. 400 x 1.05 = 420 cubic feet, or 15.56 cubic yards. 420 x 145 = 60,900 lb, which is 30.45 tons. At $100 per ton the asphalt costs about $3,045 before base material and paving labor.

A 2 in overlay on a 30 x 10 ft parking pad: 30 x 10 x (2 / 12) = 50 cubic feet, or 52.5 with waste. 52.5 x 145 / 2,000 = 3.8 tons.

Quick reference

How to calculate asphalt

Asphalt plants sell hot-mix by the ton, so the goal is to convert your paved area into weight. Multiply length by width by compacted thickness in feet for cubic feet, then multiply by 145 lb per cubic foot and divide by 2,000. A 40 by 12 foot driveway at 3 inches is 120 cubic feet, or about 8.7 tons before waste.

Always use the finished, compacted thickness in the calculation. The contractor lays the mix thicker and rolls it down by about a quarter. Add 5 percent for waste, more if the base is rough or the edges are irregular.

Driveway thickness and base

A new residential driveway needs 3 to 4 inches of compacted asphalt over 6 to 8 inches of compacted crushed stone. The base does most of the structural work; asphalt on soft or thin base will crack within a few years. Driveways that carry RVs or delivery trucks should go to 4 inches or more.

An overlay on sound existing pavement can be 1.5 to 2 inches. If the old surface has alligator cracking or heaving, milling it off and rebuilding the base costs more up front but lasts far longer. Most paving contractors have a minimum job size, so small repairs are often priced by the job rather than by the ton.

Key facts

• Compacted hot-mix asphalt weighs about 145 lb per cubic foot, or roughly 2 tons per cubic yard.
• One ton of asphalt covers about 83 sq ft at 2 in thick, 55 sq ft at 3 in, or 41 sq ft at 4 in.
• A new residential driveway is typically 3 to 4 in of compacted asphalt over 6 to 8 in of compacted aggregate base; an overlay on sound pavement is 1.5 to 2 in.
• Asphalt is delivered at about 275 to 300°F and must be compacted before it cools below roughly 185°F.
• Loose asphalt compacts by about 20 to 25%, so 4 in of loose mix rolls down to about 3 in.

Frequently asked questions

Sources and references

• •HMA Construction Manual, Chapter 2: Mix Properties (unit weight of compacted HMA) (Iowa Department of Transportation)
• •HMA Pavement Mix Type Selection Guide, Information Series 128 (National Asphalt Pavement Association and FHWA)
• •Hot Mix Asphalt Pavement Design Guide, Tenth Edition (Maryland Asphalt Association)