Asphalt Calculator
Asphalt is sold by the ton but measured on site in feet and inches, so the job is to turn a length, a width and a thickness into a tonnage your supplier can quote. This calculator does that conversion and shows the density it used.
How it works
Multiply length by width by thickness to get the volume in cubic feet. Thickness is in inches, so divide it by 12 first: a 3 inch layer is 0.25 ft.
Multiply that volume by the weight of compacted hot-mix asphalt. The Federal Highway Administration's estimating table puts it at 145.2 lb/ft³, which is the figure this calculator uses. Divide by 2,000 to get short tons.
The thickness that matters is the compacted thickness — what you end up with after rolling, not the loose depth you spread. Loose mix settles by roughly a quarter, so if you specify a compacted 3 inches your paver will lay closer to 4 inches loose.
Formula: Tons = (length ft × width ft × thickness in ÷ 12) × 145.2 lb/ft³ ÷ 2,000
Measuring on site
- Measure the area at its widest points and treat curves and flares as the rectangles that contain them. Asphalt is cheaper to have left over than to run short mid-pour.
- For an irregular shape, split it into rectangles, run each one separately, and add the tonnages.
- Check the thickness your job actually calls for before you calculate. A residential driveway is typically 2 to 3 inches of surface course over a compacted aggregate base; a parking area carrying trucks needs more, and that decision belongs to whoever specified the pavement.
Waste and what it covers
Hot-mix is delivered hot and cannot be returned, so most crews order a small margin over the calculated figure — 5% is the usual allowance for a simple rectangle, 10% where there are edges, curves or a hand-worked apron. The waste factor here is yours to set; we don't apply a hidden one.
| Driveway | Area | Tons (no waste) | Tons (+5%) |
|---|---|---|---|
| 10 × 20 ft (single car) | 200 ft² | 3.63 | 3.81 |
| 12 × 24 ft (single, generous) | 288 ft² | 5.23 | 5.49 |
| 20 × 20 ft (two car) | 400 ft² | 7.26 | 7.62 |
| 12 × 60 ft (long approach) | 720 ft² | 13.07 | 13.72 |
Questions
- How many tons of asphalt do I need for a 2 car driveway?
- A 20 × 20 ft driveway at 3 inches compacted works out to 7.26 tons, or about 7.6 tons once you add a 5% margin. Change the thickness and the tonnage changes in proportion: the same driveway at 2 inches needs 4.84 tons.
- How much does a ton of asphalt cover?
- At 3 inches compacted, one ton covers about 55 ft². At 2 inches it covers roughly 83 ft². Coverage per ton scales with thickness, which is why the thickness figure matters more than the area for the final cost.
- Is asphalt sold by the ton or the yard?
- Hot-mix asphalt is sold by weight, in short tons, in the United States. Some suppliers quote a price per square yard laid at a given thickness, which is the same calculation with the arithmetic done for you.
- What density does this calculator use, and why?
- 145.2 lb/ft³ for compacted hot-mix asphalt, from the FHWA Central Federal Lands estimating table. Real mixes vary with aggregate and binder, so treat the result as an estimate to check against your supplier's mix-specific figure on a large job.
Sources
- Federal Highway Administration, Central Federal Lands Highway Division — Application Rates and Weights for Estimating Purposes“Hot Asphalt Mix | 2325 kg/m3 (145.2 lb/ft3)”
Figures and sources last checked by The BuilderTally Team in August 2026.