Asphalt Tonnage Calculator

Asphalt is sold by weight, but you measure your driveway by length, width and depth. Getting from one to the other needs the density of the mix, and that is the number worth being careful about, because a small error in it is a large error in what you pay for.

Compacted hot mix asphalt (HMA) runs about 145 pounds per cubic foot. A cubic yard is 27 cubic feet, so that is 3,915 pounds, or 1.9575 short tons per cubic yard, which everybody rounds to about 1.96. The familiar rule of thumb “a ton covers about 80 square feet at 2 inches” falls straight out of it, and it is a useful sanity check on any figure a calculator hands you.

Cold patch, used for repairs, is a little lighter at around 140 lb/ft³, so 1.89 tons per cubic yard.

The formula:

Tonnage = Length × Width × (Thickness ÷ 12) ÷ 27 × Density

Length and width in feet, thickness in inches, density in tons per cubic yard. The ÷ 12 turns inches into feet and the ÷ 27 turns cubic feet into cubic yards.

Typical Thickness Guidelines:

Two worked examples

A residential driveway 20 feet by 40 feet at 2 inches: 20 × 40 × (2 ÷ 12) = 133.3 cubic feet, ÷ 27 = 4.94 cubic yards, × 1.9575 = 9.67 tons.

A small parking lot 60 feet by 100 feet at 3 inches: 60 × 100 × 0.25 = 1,500 cubic feet, ÷ 27 = 55.56 cubic yards, × 1.9575 = 108.75 tons.

Order 5 to 10 percent above whatever the figure comes out at. Edges are never straight, the depth is never perfectly even, and a paving crew that runs out mid-job leaves you with a cold joint you will be able to see for the life of the driveway.

On price. Hot mix has run somewhere around 100 to 200 dollars a ton in recent years, though it tracks crude oil closely and varies a lot by region and season, so treat any figure here as a rough anchor and get a local quote. Delivery is usually billed separately and most plants set a minimum load. There is a cost field in the calculator above if you want the arithmetic done; leave it blank and you just get the tonnage.

Compaction. Loose asphalt compresses under the roller at roughly 1.5 to 1, so 1.5 inches laid gives about 1 inch finished. The density used here is the compacted density, so enter the thickness you want when the job is done, not the depth of the loose pile.