Asphalt calculator

What the asphalt calculator does

This tool converts a paving area into tons of hot-mix asphalt (HMA), because the plant sells asphalt by weight, not by area. You enter the length and width in feet and the compacted depth in inches, and it returns the square footage, the tonnage to order, the coverage one ton buys at that depth, and a planning cost. The tonnage is the number you put on the ticket; everything else is there so you can sanity-check it before you call the plant.

The formula, with a worked example

Tons = length (ft) x width (ft) x depth (ft) x 145 divided by 2,000. Compacted hot-mix runs about 145 lb per cubic foot (a standard estimating convention; dense-graded mixes fall roughly 140 to 150 lb/cf), and a ton is 2,000 lb. Depth is entered in inches, so it is divided by 12 to get feet.

Worked example: a 40 ft by 12 ft driveway at 3 inches. Area is 480 SF. Depth is 3 divided by 12, or 0.25 ft. So 40 x 12 x 0.25 x 145 divided by 2,000 = 8.7 tons. At a planning price of 110 dollars per ton, that is about 957 dollars of material before delivery and placement.

How thick should the asphalt be

Depth is where money hides, because tonnage scales straight with it: double the depth and you double the tons. For a residential driveway the standard convention is 2 to 3 inches of hot-mix over a 6 to 8 inch compacted aggregate base, with the base doing most of the structural work. Commercial parking lots and drive lanes usually run a binder course plus a surface course for a total of 4 inches or more over a deeper base. Order by the compacted depth, not the loose depth: asphalt is placed thick and rolled down, and the tonnage above already assumes the finished, compacted lift.

Tons, square yards, and coverage

Paving quantities often come off the plans in square yards, not square feet, so the handy field rule is about 0.055 tons per square-yard-inch. One square yard is 9 SF, so 9 x (1/12) ft x 145 divided by 2,000 = 0.0544 tons per inch of depth. Coverage is the same math read backward: one ton spreads about 80 SF at 2 inches, about 55 SF at 3 inches. For weight, hot-mix runs close to 2 tons per cubic yard (27 cubic feet x 145 divided by 2,000 is about 1.96 tons), which is the quick check when a supplier quotes you in cubic yards instead of tons.

Hot mix versus cold patch

Hot-mix asphalt is the structural pavement: it is delivered hot, placed with a paver or by hand, and rolled while workable, and it is what this calculator sizes. Cold patch is a bagged, ready-to-use mix for temporary pothole and edge repairs; it stays pliable in the bag and needs no plant, but it is a stopgap, not a wearing course. Size a new driveway or lot with the hot-mix tonnage here, and keep cold patch for the small fixes that cannot wait for a paving crew.

From tonnage to a paved bid

A tonnage number is one line of a sitework bid. The real estimate also carries base stone, grading and excavation, tack coat, striping, and the mobilization for a paver and rollers, and each of those comes off the plans. Ruh reads the site plan, runs the takeoff for the paving and earthwork scope, and drafts a priced estimate against your own price book, so the asphalt line traces back to the sheet it came from instead of a back-of-envelope guess. See how it works on the sitework and earthwork estimating software page.