Asphalt is bought by the ton and laid by the square foot, and the bridge between the two is depth and density. This calculator takes the length and width of the area and the finished depth you want, works out the volume, and converts it to tons at the standard hot-mix density — the number the plant will ask for when you phone the order in.
The tonnage formula
Compacted hot-mix asphalt weighs about 145 pounds per cubic foot — roughly 3,915 lb, or just under 2 tons, per cubic yard. That is why a modest driveway surprises people: 100 square feet at 4 inches is only 1.23 cubic yards of material, yet it already weighs about 2.42 tons. The density field is editable because mixes vary — a plant's specific gravity sheet is the authority for large orders — but 145 is the planning figure the industry estimates with, and small jobs will never notice the difference.
Depth: the number that decides everything
Enter the compacted depth — the thickness after the roller has passed, which is what specifications are written in. Hot mix is screeded loose at roughly a quarter more than its compacted thickness, so a 4 in finished mat is laid around 5 in loose; if you are ordering for a contractor, confirm whether their figure is loose or compacted before you compare quotes. Typical finished depths: 2–3 in for a residential overlay or light-duty driveway over a sound base, 4 in or more for new residential work, and substantially more, in multiple lifts, for commercial traffic. Depth over a weak base buys little — asphalt flexes, and what it flexes on matters as much as its own thickness.
Ordering and the last half-ton
Plants sell by the ton with practical minimums, and trucks come in fixed sizes; order a little over the calculator's figure — about 5% — because edges taper, low spots in the base drink material, and running short with a cooling load on the ground is the most expensive outcome in paving. The calculator deliberately shows exact volume and weight so you can see the raw number before rounding it the way your plant prefers.
Worked example
The defaults are a 10 × 10 ft patch, 4 in deep: volume = 10 × 10 × (4 ÷ 12) = 33.33 ft³ = 1.23 yd³, and at 145 lb/ft³ that is 4,833 lb = 2.42 tons. Scale the patch to a 20 × 20 ft driveway apron and the same math gives about 9.7 tons — tonnage grows with area, which is why small depth savings matter on big jobs.
How to use this tool
- Measure the length and width of the area in feet; split odd shapes into rectangles and add the runs.
- Enter the finished, compacted depth in inches from your specification.
- Leave the density at 145 lb/ft³ unless your plant quotes a different mix density.
- Read the tonnage, then round up — about 5% extra covers taper and low spots.
- Confirm with the plant whether quoted depths are loose or compacted before ordering.
Asphalt vs concrete for the same patch
Run the same area through the Concrete Calculator and the volumes will match — a slab and a mat of the same footprint and depth displace the same space — but the buying units differ: concrete is ordered by the cubic yard, asphalt by the ton, at just under 2 tons per cubic yard. Asphalt usually wins on first cost and speed (drive on it within a day or two), concrete on lifespan and resistance to point loads and fuel spills. Either way, both sit on the base: a few inches of compacted gravel under either material is money better spent than an extra inch of either surface.