How to use the asphalt calculator
- Measure the area to be paved in feet. For an odd-shaped driveway, add it up in the square footage calculator and enter the area here.
- Enter the compacted thickness, which is the finished depth after rolling.
- Check the assumptions. The default density of 145 lb per cubic foot and 5% extra suit most hot-mix jobs. Use your supplier’s figures if they give them.
The asphalt tonnage formula
Cubic feet = area × (thickness in inches ÷ 12)
Pounds = cubic feet × density (lb per cubic foot)
Tons = pounds ÷ 2,000
Worked example
A 20 ft × 40 ft driveway, 2 inches thick
- Area = 20 × 40 = 800 sq ft.
- Volume = 800 × (2 ÷ 12) = 133.3 cu ft.
- Weight = 133.3 × 145 = 19,333 lb = 9.67 tons exactly.
- With 5% extra for compaction and edges: 140 cu ft × 145 = 20,300 lb = 10.15 tons, the figure the calculator shows.
Asphalt coverage per ton
| Compacted thickness | Coverage per ton | Tons per 100 sq ft |
|---|---|---|
| 1.5 in | about 110 sq ft | 0.91 |
| 2 in | about 83 sq ft | 1.21 |
| 2.5 in | about 66 sq ft | 1.51 |
| 3 in | about 55 sq ft | 1.81 |
| 4 in | about 41 sq ft | 2.42 |
Figures use 145 lb per cubic foot with no extra allowance.
Asphalt or concrete?
- Cost up front: asphalt is usually cheaper to install than concrete in most of the US, though prices swing with oil prices and region.
- Climate: asphalt flexes with freeze-thaw cycles and road salt; concrete can crack and scale in very cold climates but stays cooler and harder in hot ones.
- Upkeep: asphalt needs sealcoating every few years and crack filling; concrete needs less routine care but is harder to repair invisibly.
- Use the right tool: for a concrete driveway or pad, use our concrete calculator.
Common mistakes to avoid
- Using loose thickness. Order by compacted thickness. Loose mix is about a quarter thicker before rolling.
- Forgetting the base. Asphalt sits on a compacted gravel base, which is ordered separately. Use the gravel calculator with road base for that layer.
- Mixing short and metric tons. US asphalt is sold in short tons of 2,000 lb. A metric tonne is 2,205 lb.
- Ordering to the exact decimal. Plants sell in set increments. Running short mid-job leaves a cold joint.
Frequently asked questions
How many tons of asphalt do I need for a driveway?
Multiply the area by the thickness in feet to get cubic feet, multiply by about 145 lb per cubic foot, and divide by 2,000. A 20 × 40 ft driveway at 2 inches is about 9.7 tons before any extra, or about 10.2 tons with 5% added.
How much area does a ton of asphalt cover?
At 145 lb per cubic foot, one ton covers about 83 sq ft at 2 inches thick, 55 sq ft at 3 inches, or 41 sq ft at 4 inches.
How thick should a residential asphalt driveway be?
Many residential driveways use 2 to 3 inches of compacted asphalt over a compacted gravel base of several inches. Heavier traffic, soft soils and cold climates may need more. Your paving contractor should set the thickness for your site.
What is the difference between thickness before and after compaction?
Hot asphalt is laid loose and rolled down by roughly a quarter of its depth. Pavers order by compacted thickness and weight, which is what this calculator uses. The extra allowance covers edges and uneven ground.
Is asphalt sold by the ton or the yard?
Hot-mix asphalt is almost always sold by the ton. A cubic yard of compacted asphalt weighs roughly 2 tons.