The short answer
To estimate asphalt, multiply the area in square feet by the compacted thickness in feet, then multiply by 145 lb per cubic foot and divide by 2,000 to get tons. A shortcut is 110 lb per square yard per inch of thickness. A 12 × 40 ft driveway paved 3 inches thick needs about 8.7 tons, or roughly 9.1 tons with 5% extra.
How the calculation works
Asphalt is sold by weight. To estimate the tonnage, find the volume of the paved area at its compacted thickness and multiply by the density of the mix:
- Volume = area × thickness × (1 + waste %)
- Weight = volume × density (145 lb per cubic foot by default)
- Tons = pounds ÷ 2,000
The same calculation in metric uses about 2,320 kg per cubic metre, giving tonnes.
Worked example
A 12 × 40 ft driveway paved 3 inches thick, with 5% extra:
- 12 × 40 = 480 square feet
- 480 × (3 ÷ 12) × 1.05 = 126 cubic feet
- 126 × 145 = 18,270 lb ÷ 2,000 = 9.1 tons
The square-yard shortcut agrees: 480 ÷ 9 = 53.3 square yards × 3 inches × 110 lb = 17,600 lb, or 8.8 tons before the waste allowance.
Tons of asphalt for common driveways
At 145 lb per cubic foot, before waste:
| Driveway | Area | 2 inches thick | 3 inches thick |
|---|---|---|---|
| Single car, short | 10 × 20 ft | 2.4 tons | 3.6 tons |
| Single car | 12 × 40 ft | 5.8 tons | 8.7 tons |
| Two car | 20 × 40 ft | 9.7 tons | 14.5 tons |
| Large two car | 24 × 50 ft | 14.5 tons | 21.8 tons |
Before you pave
- The base matters more than the asphalt. A well-compacted gravel base, usually 6 to 8 inches, prevents most cracking and potholes. Size it with the gravel calculator.
- Use compacted thickness. Loose asphalt is laid about 25% thicker and rolled down; quotes and this calculator use the finished, compacted figure.
- Ask your plant for the mix density. If your supplier gives a specific density for the mix, enter it in place of 145.
Frequently asked questions
How much does asphalt weigh per cubic foot?
Compacted hot-mix asphalt usually weighs 145 to 150 lb per cubic foot. Open-graded mixes with more air voids are lighter, around 125 to 135 lb.
How thick should an asphalt driveway be?
Residential driveways are typically 2 to 3 inches of compacted asphalt laid over a 6 to 8 inch compacted gravel base. Heavier vehicles call for a thicker base and surface.
How many square feet does a ton of asphalt cover?
At 145 lb per cubic foot, one ton covers about 83 square feet at 2 inches thick, or about 55 square feet at 3 inches.
What is the 110 lb per square yard rule?
It is a paving shortcut. One square yard of compacted asphalt one inch thick weighs about 110 lb, so tons = square yards × inches × 110 ÷ 2,000.
Should I add extra?
Yes. Add around 5% for waste, edges and uneven base. Plants often round orders up to the nearest ton anyway.
Sources
Related calculators
About this calculator. Every formula on this page is tested against worked examples from the sources above before publishing. Results are estimates for planning; confirm with your supplier or local code.
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